Fuel EXe Trek Fuel EXe Megathread!
- Thread starter Rob Rides EMTB
- Start date
Emailsucks98
Active member
Looks like the profile is different and maybe the length too. Who knows what the future holds!
DugT
Active member
How do you solve the noisy two lowest gears problem? It is my understanding that the increased cross chaining angle causes it. I wax my chain which is a bit of a chore but I used to get a few hundred miles between waxing. Now, with this bike, the low gears get noisy after about 30 miles. Is there a way to just lube those two gears? I think the noise is coming from the cassette and not the chainring but I'm not positive.
Hey, noticed a similar issue on my EXe, I also wax my chains and get around 80-120km's before I start noticing noise in the easier gears. And like you say it's only at the gears at the big end of the cassette, silent everywhere else. While looking at the chainline while installing a E13 guide on my wife's 9.5 EXe, it's not great, fairly crossed up as you mentioned. I can say that my YBN chain (Black SLA1210) is quieter than the Shimano Hyperglide XT's I alternate with. Feels like it has tighter lateral tolerances in the links and pins. When it comes time for new chains it will be only YBN, the black coating on it has also been impervious to the surface rust the XT suffers from. I don't find waxing a chore at all, it's far less faf than the regular degreasing of the chain, sprockets and jockey wheels followed by careful relubing. I run several chains, and when all are used process them as a batch, then ride for months!
Scarboroguy
New Member
Has anyone had experience with the upper trunnion shock bolts? One snapped removing it. They seem super soft and Im snapping them at 15NM. I wonder if they are a one use item.
I've had my shock off many times, but haven't snapped those bolts. You have to ensure you push the Allen key as far into the bolt as you can otherwise you might shear the 'cap' off
Last edited:
wheelsx2
Member
No issues here, and I have changed my shock a lot.
My one fear with most Treks is all the custom hardware. I intend to buy spares for all the custom bit, for just this situation.
If you can, you might get your torque wrench checked. Also, dry threads as well as overly locktited threads and make the torque wrench not work as expected.
Scarboroguy
New Member
Thanks for the input. Might be not pressing in enough thats what happened the cap sheared.. I had them started by hand and used two different torque wrenches both that I trust and as I mentioned after the first snapped I reduced to 15 nm from 17 nm. No extra loctite applied. I had a bunch of F.S. bikes and never had this happen. Im cornering the market on them now L.O.L.
Scarboroguy
New Member
The bolts come pre blue Loctite applied. should I remove and or grease ?
I posted this on the Trek Fuel EXE owners group on FB but thought you guys might find it useful too.
Some of the information has already been mentioned by members here, but I've just collated it and put some more insight into it from my findings.
---------------------------------------------------------------------------------
Trek Fuel Lower Pivot Bolt Play Solution
Legends,
– Short version –
The issue of lower shock mount play is solved with a custom pivot bolt. Check the bottom of this post if you’re interested in obtaining one. Otherwise to gain more insight, read the long version.
– Long version –
As you may have experienced first hand or read about it here or on forum, Trek Fuel EXE owners have reported play in the lower pivot bolt. By play, I mean vertical movement between the shock bolt and hardware.
How to check if your bike has this issue:
Loosen your lower pivot bolt. Put one hand on the seat tube below the seat collar and another on the rear triangle holding it down. Pull up with the seat tube hand and you’ll hear a clicking coming from the lower shock mount. You can pull on the seat tube with your other hand under the lower shock mount and you’ll feel the movement. Repeat this at 10NM, 13NM and 15NM.
10 and 13 you should still feel the movement, and 15 is about where the horizontal force is greater than the weight of the bike so you won’t feel it.
What is actually causing this?:
There is a very small gap between the bolt and shock hardware (regardless of Fox, Rockshox etc).
The cause of this is that Trek decided to use a generic off the shelf M8x60 threaded bolt. You can get these for as low as $2. Turns out that all off the shelf M8x60 bolts have a diameter of 7.85mm. This is an industry standard. Surely this would be a common issue for many bikes then? No it isn’t because the majority have their pivot bolts custom made. For example both shock bolts on a Canyon Torque measured at 7.97mm. All shock hardware measures in at about 7.99mm.
Trek’s Recommendation:
Trek issued a bulletin regarding this (it was directed only at Fox shocks but it applies to all kinds of shocks). Their solution was to replace the hardware and tighten the bolt to 15NM. The torque rating used to be lower in the original Trek manual.
Essentially it’s a bandaid fix because tightening the bolt more will apply more horizontal force to clamp the hardware tighter to the frame. Which means when your bike is static, you won’t feel the play because the horizontal force is greater than the force you apply when wiggling the seat tube. It will appear to have no play but in reality, it will still move under big compressions and decompressions when riding. If you forcefully push and pull the seat tube then you will feel the play still there. This can also lead to extra stress and wear on the frame that over time, you’ll have to tighten it a bit more and more.
The recommendation of replacing the hardware and even supplying a new shock bolt will have zero effect as you’ll still end up with ~0.14mm gap. You may get lucky and get an out of tolerance bolt that is thicker, but there is another problem with this off the shelf bolt.
I’ve advised Trek APAC Support of my findings regarding the bolt and I’ve either been given a generic response of “replace your hardware” (even though in my email I wrote that I did) or just been ignored.
Bonus problem with the Trek supplied bolt:
This is the part that really gives me the sh*ts. The off the shelf bolt that comes with the bike has an excessive thread length. Rather than just being the length of the little nut that sits on the side of the frame (around 8mm), it's almost half the length of the bolt at ~30mm.
This means that about half of your shock hardware will be rotating on thread splines rather than a smooth bolt surface. This will cause your shock hardware to wear out quicker. Which means you’ll have even more play.
Some engineer, well actually multiple people at Trek, would’ve looked at this design spec and said ‘Yes, this is acceptable for a $5000+ bike … lets spend $2 on half assed choice rather than $20-30 on the optimal choice’.
How this problem is solved:
Firstly, full credit goes to @Jazzii . He posted his findings on the EMTB Forum and I used that as a basis.
The fix is that you need an M8x60 bolt with a 1.25 thread of ~10mm, shaft diameter of 7.99mm and head diameter of 13mm.
The way to achieve this is to get an M10x80 bolt machined down to this spec.
As simple as this sounds, it took quite a bit of asking many local places and prototype trial and error. Some things I learned:
How you can get one:
I’m putting out an expression of interest for these to owners like yourselves.
Ideally I would order in bulk as it’s easier for the machinist and will take a few bucks off the bolt.
The price of the bolt will be AUD $50 posted anywhere in Australia.
NZ I can probably post to you guys.
If there is high interest in Europe and the US then I can try to get postage quotes for you also.
I’m not looking to make a profit on this. Just to cover the manufacturing cost, postage and recoup costs in two failed prototypes at other machinists.
It’s made from stainless steel. Due to it originally being an M10 head, the head will protrude about 1-2mm from the frame which is negligible as the rear triangle behind it protrudes way more. Black anodizing and head length machining will only add to the cost and add no functional value.
Attached are photos of the bolt, and two videos (EMTB didn't allow videos so check my post on FB). The videos are of each bolt, demonstrating the movement and sound when the bolt is loose and when it is hand tightened. (see ‘How to check if your bike has this issue’ above to do this yourself)
I’ve also attached a design drawing that you can provide to a machinist if you wish to have this manufactured yourself.
Let me know if you’re interested in purchasing one so I can gauge numbers and put an order in the next few weeks.
If there’s any questions, then feel free to ask.
Some of the information has already been mentioned by members here, but I've just collated it and put some more insight into it from my findings.
---------------------------------------------------------------------------------
Trek Fuel Lower Pivot Bolt Play Solution
Legends,
– Short version –
The issue of lower shock mount play is solved with a custom pivot bolt. Check the bottom of this post if you’re interested in obtaining one. Otherwise to gain more insight, read the long version.
– Long version –
As you may have experienced first hand or read about it here or on forum, Trek Fuel EXE owners have reported play in the lower pivot bolt. By play, I mean vertical movement between the shock bolt and hardware.
How to check if your bike has this issue:
Loosen your lower pivot bolt. Put one hand on the seat tube below the seat collar and another on the rear triangle holding it down. Pull up with the seat tube hand and you’ll hear a clicking coming from the lower shock mount. You can pull on the seat tube with your other hand under the lower shock mount and you’ll feel the movement. Repeat this at 10NM, 13NM and 15NM.
10 and 13 you should still feel the movement, and 15 is about where the horizontal force is greater than the weight of the bike so you won’t feel it.
What is actually causing this?:
There is a very small gap between the bolt and shock hardware (regardless of Fox, Rockshox etc).
The cause of this is that Trek decided to use a generic off the shelf M8x60 threaded bolt. You can get these for as low as $2. Turns out that all off the shelf M8x60 bolts have a diameter of 7.85mm. This is an industry standard. Surely this would be a common issue for many bikes then? No it isn’t because the majority have their pivot bolts custom made. For example both shock bolts on a Canyon Torque measured at 7.97mm. All shock hardware measures in at about 7.99mm.
Trek’s Recommendation:
Trek issued a bulletin regarding this (it was directed only at Fox shocks but it applies to all kinds of shocks). Their solution was to replace the hardware and tighten the bolt to 15NM. The torque rating used to be lower in the original Trek manual.
Essentially it’s a bandaid fix because tightening the bolt more will apply more horizontal force to clamp the hardware tighter to the frame. Which means when your bike is static, you won’t feel the play because the horizontal force is greater than the force you apply when wiggling the seat tube. It will appear to have no play but in reality, it will still move under big compressions and decompressions when riding. If you forcefully push and pull the seat tube then you will feel the play still there. This can also lead to extra stress and wear on the frame that over time, you’ll have to tighten it a bit more and more.
The recommendation of replacing the hardware and even supplying a new shock bolt will have zero effect as you’ll still end up with ~0.14mm gap. You may get lucky and get an out of tolerance bolt that is thicker, but there is another problem with this off the shelf bolt.
I’ve advised Trek APAC Support of my findings regarding the bolt and I’ve either been given a generic response of “replace your hardware” (even though in my email I wrote that I did) or just been ignored.
Bonus problem with the Trek supplied bolt:
This is the part that really gives me the sh*ts. The off the shelf bolt that comes with the bike has an excessive thread length. Rather than just being the length of the little nut that sits on the side of the frame (around 8mm), it's almost half the length of the bolt at ~30mm.
This means that about half of your shock hardware will be rotating on thread splines rather than a smooth bolt surface. This will cause your shock hardware to wear out quicker. Which means you’ll have even more play.
Some engineer, well actually multiple people at Trek, would’ve looked at this design spec and said ‘Yes, this is acceptable for a $5000+ bike … lets spend $2 on half assed choice rather than $20-30 on the optimal choice’.
How this problem is solved:
Firstly, full credit goes to @Jazzii . He posted his findings on the EMTB Forum and I used that as a basis.
The fix is that you need an M8x60 bolt with a 1.25 thread of ~10mm, shaft diameter of 7.99mm and head diameter of 13mm.
The way to achieve this is to get an M10x80 bolt machined down to this spec.
As simple as this sounds, it took quite a bit of asking many local places and prototype trial and error. Some things I learned:
- Most shops don’t want to deal in quantities of just one.
- If they deal in one, the cost usually is pretty high $100-$150.
- Not all machinery can deal with such a small bolt.
- Getting to exact 7.99mm accuracy evenly can be tough.
How you can get one:
I’m putting out an expression of interest for these to owners like yourselves.
Ideally I would order in bulk as it’s easier for the machinist and will take a few bucks off the bolt.
The price of the bolt will be AUD $50 posted anywhere in Australia.
NZ I can probably post to you guys.
If there is high interest in Europe and the US then I can try to get postage quotes for you also.
I’m not looking to make a profit on this. Just to cover the manufacturing cost, postage and recoup costs in two failed prototypes at other machinists.
It’s made from stainless steel. Due to it originally being an M10 head, the head will protrude about 1-2mm from the frame which is negligible as the rear triangle behind it protrudes way more. Black anodizing and head length machining will only add to the cost and add no functional value.
Attached are photos of the bolt, and two videos (EMTB didn't allow videos so check my post on FB). The videos are of each bolt, demonstrating the movement and sound when the bolt is loose and when it is hand tightened. (see ‘How to check if your bike has this issue’ above to do this yourself)
I’ve also attached a design drawing that you can provide to a machinist if you wish to have this manufactured yourself.
Let me know if you’re interested in purchasing one so I can gauge numbers and put an order in the next few weeks.
If there’s any questions, then feel free to ask.
DugT
Active member
Thanks for the excellent post about Trek's inadequate bolt. You said that other bike companies use a custom bolt to solve this problem. Can we buy better bolt from them? However, if that was a solution, this really wouldn't be a problem.
Maybe I misunderstood but why do many suppliers of Shock's design their shocks to require a custom bolt instead of the standard? Since they didn't, I'm sure the shock suppliers warn the customers, like Trek.
I'm surprised that Shock suppliers don't have custom bolts made that they supply with their shocks. It seems to me, several sources failed to provide an adequate solution.
In the meantime, to solve the bolts threads wearing the frame, a temporary solution could be to fill the excess threads in with epoxy. Lathe off the excess epoxy. Grease that bolt and see how the epoxy holds up to the friction.
Maybe I misunderstood but why do many suppliers of Shock's design their shocks to require a custom bolt instead of the standard? Since they didn't, I'm sure the shock suppliers warn the customers, like Trek.
I'm surprised that Shock suppliers don't have custom bolts made that they supply with their shocks. It seems to me, several sources failed to provide an adequate solution.
In the meantime, to solve the bolts threads wearing the frame, a temporary solution could be to fill the excess threads in with epoxy. Lathe off the excess epoxy. Grease that bolt and see how the epoxy holds up to the friction.
Perfectly described problem and solution. We where lucky here in Slovakia. We asked clever guys in local garage and they made for me and my friends 5 custom bolts just for 100€. Crazy how big company like Trek is can owerlook and ignore it for two years now.
bk12
Member
What an excellent post. I don't believe I can send private messages here (not enough posts maybe?), but I am very interested, but located in the US. Can you let me know if you are willing to ship our way, and what the cost of one of these would be? Thanks
gmoss
New Member
Mcmaster Carr has bolts to fit, but have the longer threads. I wonder if a longer bolt can be bought, and then cut, and tapped with a new shorter 1.25 pitch thread? Idk if the bolt siamter is on point, but may be worth a try.
All shock hardware which is mass produced are ~7.99mm.
All off the shelf general purpose M8 bolts are ~7.85mm.
The usage of bolts as pivots for bikes makes up like probably 0.001% of worldwide bolt usage.
I think if shock manufacturers made shock bolts then it would potentially limit frame design as there's lots of variables that I've seen in different frames such as:
- Yoke application
- Different kinds of size and shape (button or flat) recesses in the frame
- Shoulder bolt application
- Different length threads
So I think the responsibility is currently in the right spot, just they may not always get it right.
Thanks! I'll get a quote this week and see how viable it is for you.
You can find my post on the Trek Fuel EXE facebook group and just give me a message there for more details.
Yeah they did a really good job considering how painful it was for me to find a shop to do it to that precise tolerance. Thanks again!
That place looks very similar to the general purpose bolt specialist sites I enquired about and they all told me the diameter was 7.85mm. I originally thought exactly what you suggested because it's the most logical but turns out it wasn't so straight forward
gmoss
New Member
May be true, but until a call is made to McMaster Carr, its an assumption. If they sell military grade, would think it at least would be worth a call. I may do that this week.
Usually thats the quality of materials used and finished, rather than dimensions ... but please do check! Would be a good alternative if theirs is 7.99 off the shelf
DugT
Active member
I know just enough to be dangerous. How about getting a bolt that is a little too narrow and having it chrome plated. If that made it too thick, that problem is easier to solve.
Emailsucks98
Active member
getting a custom DU bushing with a smaller ID would be a less complicated fix.
Not sure that will help? bushing interfaces with the outside of the mounting hardware. But if you have a Rock Shox you have a long pin spacer that passes though the mounting hardware and the both passes through that, so I'm pretty sure it will be cheaper and easier to make a new pin sleeve than a bolt. Much less machining, length, OD on a lather and drill out the ID to match the stock generic bolt. It might be worth looking for a longer generic bolt with a longer smooth shank and cut it down to have less thread in the sleeve. Not sure how the Fox hardware works.
What would a smaller DU bush solve when its actually due to a gap between the mounting hardware and the bolt?
Do you mean mounting hardware? They are considered consumables as they wear over time (especially if its rotating on threads).
Is custom mounting hardware really considered an optimal or even less complicated fix since you'll be getting 1 or 2 fabricated every season, plus keeping a spare on hand? Rather than a one off bolt that fits all Rockshox and Fox hardware you can find anywhere.
I've never seen properly installed mounting hardware wear or fail, unless you have an issue like play in the bolt that damages the softer hardware aluminium. Your solution will work great, but at that price for a bolt, someone who has a Rock Shox and no desire to fit a Fox might prefer to just get the sleeve done (it should cost less and less hit and miss given the simpler machining), the rest of the hardware is unchanged. It's not an argument, its another solution...
Hey!
I am also from Slovakia with the same issue - knocking lower shock mount. Any chance you have one of this custom bolt for sale?
Thanks!
Emailsucks98
Active member
Good point - I don't have this issue with my EX-e, I see what you're saying now. Still, custom shock hardware would be a much simpler solution. Just simple aluminum reducers, no threads or hex keys to machine. The lower mount on our bikes sees almost no rotation, so wear isn't an issue. RWS already has kits to deal with shock bores out of tolerance, I'd think it would be worth checking with them.
Shock Eyelet Bushing Kits | Real World Cycling
gmoss
New Member
I am running their lower shock bushing kit. I did not notice any play when I installed my X2, but I will check again.
The hardware will still be sitting on the threads of the Trek bolt which just doesn't sit well with me. Even though there isn't much rotation as you said, wear is an issue as the threads will eat at the aluminum over time ... which then you'd have to buy the same replacement and end up being the same cost as the custom bolt.
If the bolt was completely smooth and only had thread on the tip, then for sure, I'd be completely aligned with your idea.
Thanks for the link! I shot RWC an email to see what their ID of their 40mm hardware is out of curiosity
I've seen it more prevalent in smaller hardware ... usually because of twisting forces under load applied due to the frame design ... like my previous bike that had a yoke, I had to replace that hardware once a season.
For the Fuel EXe then totally agree with you, it (theoretically) shouldn't wear at all but I've found mountain biking to be unpredictable at times
Definitely not an argument, I enjoy discussions like these and exploring alternative solutions.
Last edited:
DugT
Active member
To solve the bolt threads inside the frame problem, I still like the idea of sanding off the sharp thread edges and then filling in the extra threads with extra hard epoxy with fiberglass particles in it.
I asked in garage for this and was told, that its technically MUCH EASIER to make 7,99 mm outer diameter bolt then to make 0,01 mm wider inner diameter of mounting sleeve/hardware. And, second problem is, that standard bolts are not produced within 0,01 mm tolerance, so every bolt would need custom sleeve. Anyway its fun for me to read how big talk is about one absolutely easy job - precise bolt. Two years ago I bought exe, shock was knocking, I measured the original bolt, was small in standard 8mm mounting hardware. I went to local garage, asked for five custom bolts, were made in two days and problem was solved. I posted it here much later, because was wondering how strange stupid solutions where written here, like "change rock shox for fox mounting hardware" etc... Dont get crazy, take your bike to local garage, ask for custom bolt and you will forget for this problem forever.
Emailsucks98
Active member
I would like to know their logic. Let's say you used the stock bushings, custom reducers could easily be turned down on a lathe from aluminum (if not CNC'd or even 3D printed). Going a step further, you could start with a fox hardware kit and replace only the inner sleeve- a simple tube. Machining threads and a bolt head out of steel (or stainless) seems inifinitely more complicated.
Burgtec is another company to keep in mind. I wonder if their santa cruz bolt kits might include a match for the EXe.
https://burgtec.co.uk/product-category/products/bolt-kits/
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