Are my front forks faulty?

[ShinySideUp]

I put this in the Cube forum but it's a general question on forks so I repeat it here with the expectation of a wider audience and hopefully a bit of help:

I bought a Cube Reaction Hybrid Pro 625 a couple of weeks ago.

When I got the bike home I noticed on my first ride out that the suspension was bottoming out so wondered what was wrong. Never having had air forks before I quickly realised that they were not set up for my weight. Bought a shock pump and got them up to recommended 110 PSI (I weigh a stout 100kgs). All seemed fine until I noticed something odd that does not happen on my coil suspension in my standard MTB. When I'm going downhill and have to brake, the suspension compresses, as you would expect, but after releasing the brakes, the suspension stays down until I start pedalling or deliberately lift the weight off the forks so if I brake on rough ground I effectively have no suspension travel until it corrects itself. At all other times -- bad roads, rocks etc. -- the suspension seems to work normally. I have tried pumping it up until it no longer happens but then the suspension is so hard it doesn't compress at all. It's as if there is a stickiness inside the forks that only shows itself under braking. I thought it might be because they are new but after 150 miles it is still happening. Are these forks just rubbish or is there a fault -- or have I just got it set up all wrong. There is no rebound damping adjustment and I have tried all positions for the preload. I have also experimented with various pressures too. My personal opinion is that they are faulty but since they appear to work in all other situations I'm not sure why that would be.

Help.

 

[Justinitus]

Which fork is it you have?

 

[ShinySideUp]

X-Fusion Mig29 32. I'm pretty sure they are a long way from top of the range but then so were the forks on my standard bike and they work fine.

 

[urastus]

To get one of the basics out of the way, while you're pumping up your fork, do you equalize the pressure? Are you aware of this?

If not look from 3'50'' into this video for explanation

 

[skinipenem]

A bit confused as to your description of the adjustments available on your fork. Pr ler xfusion website:

MIG 29

Weight : 3300 grams(STKM)/ 2740 grams(AL)

Wheel Size : 29 inch

Travel : 100mm,120mm,130mm

Stanchion : 32mm(STKM, Cr-Plating/ AL)

Spring : Coil(Soft, Standard, Firm), Air spring

Damper : RC, LO

Adjustment : 1. Compression, Rebound, Preload spring

2. Lock without ReboundSteerer : Taper(STKM)

Axle: 9-100mm or Boost 15-110 Dropout

Offset : 51mm

Max Rotor Size: 180mm

Seems your Rebound adjustment may be off. Could be negative air pressure chamber. Could be too little air pressure and the seals need to break in? Try adjusting the Preload spring to a stiffer one (guessing here.)

 

[SurreySteve]

To get one of the basics out of the way, while you're pumping up your fork, do you equalize the pressure? Are you aware of this?

To get one of the basics out of the way, while you're pumping up your fork, do you equalize the pressure? Are you aware of this?

If not look from 3'50'' into this video for explanation

^^^^THIS^^^^

Assuming your forks have a single air valve (and not separate positive and negative)
If they are single air valve then inside is a little dimple and when the shaft passes it should equalise pressure between the main (positive) chamber and underneath (negative)

If this port get blocked by too much grease this can also cause the issues you describe.

 

[ShinySideUp]

To get one of the basics out of the way, while you're pumping up your fork, do you equalize the pressure? Are you aware of this?

If not look from 3'50'' into this video for explanation

That is most interesting, I shall go and check this out today.

 

[ShinySideUp]

A bit confused as to your description of the adjustments available on your fork. Pr ler xfusion website:


Seems your Rebound adjustment may be off. Could be negative air pressure chamber. Could be too little air pressure and the seals need to break in? Try adjusting the Preload spring to a stiffer one (guessing here.)

Unfortunately, the X-Fusion website doesn't seem to hold the correct information regarding rebound. As far as I can see there is NO rebound adjustment on my forks, there's just the preload at the top of the right stanchion (as seen from on the bike) and nothing else anywhere apart from the air valve on the left stanchion. I shall follow the instructions in the video above and see what that does.

 

[SurreySteve]

That is most interesting, I shall go and check this out today.

Irrelevant if they have separate valves for the chambers though.

 

[ShinySideUp]

Irrelevant if they have separate valves for the chambers though.

Mine don't.

Have checked long and hard though and there is also definitely no rebound control, which is a shame; get what you pay for I guess.

Not really buyers remorse but I sort of wish I'd paid the extra one and a half grand for a Whyte with Rockshox, this one will probably see me out now though.

 

[Konanige]

According to the website you should have a red rebound knob on bottom of right hand leg! Getting a fork without rebound damping would be pretty hard these days I would have thought.

 

[ShinySideUp]

According to the website you should have a red rebound knob on bottom of right hand leg! Getting a fork without rebound damping would be pretty hard these days I would have thought.

I regret to say, you thought wrong. The only thing on the right (and the left) fork is an allen socket which, from my knowledge of motorcycle forks, is merely a retaining bolt for the innards. It just goes to show that Cube have got a job lot of crappy forks for this bike. I'll live with them for now but TBH, it's all left a bit of a bad taste as I love the rest of the bike.

This is the website that's relevant to this bike and as you can see, there is no reference to rebound on the forks:

Hybrid Pro

 

[Hardtail]

I regret to say, you thought wrong. The only thing on the right (and the left) fork is an allen socket which, from my knowledge of motorcycle forks, is merely a retaining bolt for the innards.

I think you have lost your knob!
See this video of the similar RC32. You can see the red anodised adjuster in the images on the X-Fusion website: MIG

 

[SurreySteve]

Mine don't.

Have checked long and hard though and there is also definitely no rebound control, which is a shame; get what you pay for I guess.

Not really buyers remorse but I sort of wish I'd paid the extra one and a half grand for a Whyte with Rockshox, this one will probably see me out now though.

I regret to say, you thought wrong. The only thing on the right (and the left) fork is an allen socket which, from my knowledge of motorcycle forks, is merely a retaining bolt for the innards. It just goes to show that Cube have got a job lot of crappy forks for this bike. I'll live with them for now but TBH, it's all left a bit of a bad taste as I love the rest of the bike.

This is the website that's relevant to this bike and as you can see, there is no reference to rebound on the forks:

Manufacturers sometimes get OEM forks.. I kid had an old Cannondale came without rebound even though the fork manual etc. said it had.

They all do it so it's more to do with going for the low/entry end bike more than specific manufacturers.

A friend bought a cheap entry Orbea (analogue) I think is the scariest bike I ever rode. (Bear in mind I've ridding gnarly stuff on a kids 16" wheel bike) ... the whole frame is badly balanced (well it's not balanced) .. forks clank horribly on extension... brakes are non existent.
YET both Cube and Orbea make some really nice bikes.

What really matters is if its worth or even can be upgraded ... you have a grands worth of motor and battery
I'm not optimistic given they have a step through version of that bike. (Sorry)
On the other hand my bike is an old (2017) bottom end Trek ... the only original parts of the frame/motor/battery (and stem/bars/seatclamp) .. the difference is Trek just wrecked a perfectly good bike rather than created a crap frame specially.

 

[Konanige]

I regret to say, you thought wrong. The only thing on the right (and the left) fork is an allen socket which, from my knowledge of motorcycle forks, is merely a retaining bolt for the innards. It just goes to show that Cube have got a job lot of crappy forks for this bike. I'll live with them for now but TBH, it's all left a bit of a bad taste as I love the rest of the bike.

This is the website that's relevant to this bike and as you can see, there is no reference to rebound on the forks:

Hybrid Pro

Have a look in the bottom Allen bolt it may have a hole in the head to accept a smaller Allen key to adjust the rebound. Rockshox have similar and the red adjuster knob used to fall out for a pastime!!

 

[ShinySideUp]

This is the view of the bottom of my forks, as you can see there is no rebound control, I'll just have to accept that's the way it is. I think the forks are not faulty but just somewhat inferior to what I am used to. To be honest, if I want to do some serious off-roading I'll just get my non-electric bike out, it's just a shame about the problem I will continue to have with suspension that doesn't work the way I want it to. This is my first outing into air forks, makes me long for a nice coil spring .

 

[urastus]

How did you go with equalizing pressure? Did you understand it? Basically as your pumping up your shock every 5 or 10psi push down on the fork.

 

[neilo]

Even the cheapest after-market air forks I've seen have rebound control. I'd throw that in the bin and get a new one. Maybe something like an SR Suntour XCR 34?

Although the fact that it won't work right at 110psi is weird. If anything, the rebound should be too fast at that pressure. They should have set the rebound speed for an average rider weight / pressure and you're probably a little heavier than the average. I would try and find a bike mechanic to take a look.

 

[ShinySideUp]

How did you go with equalizing pressure? Did you understand it? Basically as your pumping up your shock every 5 or 10psi push down on the fork.

Yes, I went through that as per the video.

 

[ShinySideUp]

Even the cheapest after-market air forks I've seen have rebound control. I'd throw that in the bin and get a new one. Maybe something like an SR Suntour XCR 34?

Although the fact that it won't work right at 110psi is weird. If anything, the rebound should be too fast at that pressure. They should have set the rebound speed for an average rider weight / pressure and you're probably a little heavier than the average. I would try and find a bike mechanic to take a look.

It coming up for it's first free service so we'll see what they've got to say.

 

[RustyMTB]

I've seen forks before with great big gobs of grease smeared in the lowers from the factory that behaved in the way you describe with the excess grease preventing air flow, It is possible you have a Friday afternoon fork on your bike. As you mention, get it pulled apart & see what's what. If it is assembled correctly, then it's either live with it or junk it for something better & you do have options in that regard.

We're all different but I would be very happy wth something used that I put in the stand & renew to factory fresh but I realise doing that is not for everyone but even then, you should be able to pick something up from PB/Ebay etc. & have the bike shop refresh for not very much & therefore avoid dropping ££££ on a shiny new prong.

 

[Richridesmtb]

I'm assuming you have warranty on the bike? If so, tell them to get the forks working or fit new ones that do. If the cheap nasty ones are hopefully unavailable you could, hopefully, get a reasonable deal on some upgraded ones.

They are not working properly. Don't accept rubbish, too many consumers do and the manufacturers get away with it.

 

[ShinySideUp]

After a little more pratting about this morning I am comfortable that it is not me and that I'm not doing something untoward so while it is a 60 mile round trip I took it back this morning and left it with the dealer. I'll let you know in a few days how it's going. In the meantime thanks for all your help.

 

[ShinySideUp]

Sorry if this post is rather long but it serves both to bring the story to it's probable conclusion and to say how I feel about the whole experience and finally, what I think about the bike in general:

Well, the bike has been in to the dealer, the forks sent away and 'repaired' -- the service note said they'd replaced one of the lowers and fixed a broken actuator pin, whatever that is. The result? Nothing. The forks are exactly the same and behave the same.

Now I checked the forks before I left the dealer, I rode it around and around the car park (which handily has a steep slope on it) for about ten minutes. I had one of the technicians also ride it around the same car park and he agreed that what I was experiencing was what he experienced too. I could see we were getting nowhere so as he was looking at the forks I noticed that there in the showroom was an exact same bike. Ah, thinks I, let's do a comparison. I said to the salesman (who had taken the place of the technician as by now I was getting a little irate) that if the other bike exhibited the same symptoms then I would have to accept that whatever we both thought of the forks they were actually working the way they were designed. I duly rode the replacement bike in exactly the same manner (with exactly the same pressure settings) and guess what? It behaved exactly the same!

The upshot of this whole exercise can be summed up as follows: The bike is entry level. They have put in a good motor and battery but have had to compromise in a big way in another area -- the suspension. What I have done, or rather not done, in buying this bike is to ensure that it was the right one for my riding style. The blurb says this is a go-anywhere bike and as I don't do any serious off-roading, just roads and trails, this might have seemed a good buy however it would seem that what I consider a trail and what Cube consider a trail are vastly different. I'm not going to change the bike, I may not even change the forks as now I know their shortcomings and know there is actually nothing wrong with them (except that they are a bit naff) I can live with them and their limitations.

I would expect that if someone bought this bike for road use with occasional forays onto unpaved cycle tracks they may not even notice that the forks are not very good and only if they hit serious rocks and potholes would they feel a little 'un-suspended'. If the road/cycle-trail experience is the way you ride then I can recommend this bike as it is effective and really quite comfortable and has an entry-level price. If you think for a minute you might occasionally try charging down a rocky dry stream bed then I strongly suggest putting in another £1500-£2000 for better parts (or get this bike and change the forks).

Anyway, for now, it'll do. I am enjoying riding it again, it is getting me much further for the same effort I would use on a non-ebike and that does make it a lot more fun. Whether at my age (68 in a couple of months) I'll ever upgrade remains to be seen but it's not likely.

Thanks for all your help on this matter but it is unfortunate that we were all trying to fix a fault that was never really there.

 

[Richridesmtb]

They should have replaced the flux capacitor.

Sounds like you should track down a new fork. You can find good ones people take off new bikes at a discount.

 

[urastus]

I noticed that there in the showroom was an exact same bike

Did you happen to look at the other fork to see if it had a rebound damper adjustment? I just had a thought - on my forks I could easily replace the hollow bolt with a normal bolt, and therefore nowhere for a rebound adjuster to go.

I bought a budget bike, a 2020 merida e140 ltd (aluminium). It has rockshox 35 gold rl forks - they are probably the most complained about forks here . I'm still not sure I could tell the difference between these forks and much higher end ones. My focus has always been to get the most out of the bike that I can. That means maintenance and adjusting everything to suit what I do. Given my riding skill I have never thought that this bike is holding me back. Well, I did have to beef up the brakes, they were under par for where I ride, and I did gear the bike down a bit to also suit the steep country and my near constant use of a modified (lower power) eco mode. Relatively cheap and minor changes. I would choose differently next time, but now I know why. The interesting thing is that if I had to choose right now, it wouldn't be that much different - an e160 700

 

[ShinySideUp]

Did you happen to look at the other fork to see if it had a rebound damper adjustment? I just had a thought - on my forks I could easily replace the hollow bolt with a normal bolt, and therefore nowhere for a rebound adjuster to go.

I bought a budget bike, a 2020 merida e140 ltd (aluminium). It has rockshox 35 gold rl forks - they are probably the most complained about forks here . I'm still not sure I could tell the difference between these forks and much higher end ones. My focus has always been to get the most out of the bike that I can. That means maintenance and adjusting everything to suit what I do. Given my riding skill I have never thought that this bike is holding me back. Well, I did have to beef up the brakes, they were under par for where I ride, and I did gear the bike down a bit to also suit the steep country and my near constant use of a modified (lower power) eco mode. Relatively cheap and minor changes. I would choose differently next time, but now I know why. The interesting thing is that if I had to choose right now, it wouldn't be that much different - an e160 700

No, no rebound adjustment on the other bike either, it was exactly the same model. It's a bit of a shame really as on a bike that costs three grand, an extra fifty or a hundred quid for rebound adjustment wouldn't have made a whole lot of difference. I suppose they were aiming for a suitable profit margin while still keeping the retail price below 3K -- which they did as the price was actually £2,999 (hey lucky me, I saved a pound).

 

[urastus]

I don't think rebound is as important on the front - it definitely is on the rear. I have adjusted a couple of clicks rebound as listed by the sram online guide - I wouldn't notice or feel how to do it otherwise. The rear is a definite feel though - pogoing after dropping off a kerb is a good test for the shock, but I never feel this for the fork. I've often added some rebound on trail after playing with shock pressures.

 

[Nutloose]

I couldn't get on with the Suntour forks on my Reaction Pro 500 so I swapped them over for the Marzocci Bomber Z2 130mm.
The extra travel may have helped some, but the ride quality is loads better.

 

[Netty]

Sorry if this post is rather long but it serves both to bring the story to it's probable conclusion and to say how I feel about the whole experience and finally, what I think about the bike in general:

Well, the bike has been in to the dealer, the forks sent away and 'repaired' -- the service note said they'd replaced one of the lowers and fixed a broken actuator pin, whatever that is. The result? Nothing. The forks are exactly the same and behave the same.

Now I checked the forks before I left the dealer, I rode it around and around the car park (which handily has a steep slope on it) for about ten minutes. I had one of the technicians also ride it around the same car park and he agreed that what I was experiencing was what he experienced too. I could see we were getting nowhere so as he was looking at the forks I noticed that there in the showroom was an exact same bike. Ah, thinks I, let's do a comparison. I said to the salesman (who had taken the place of the technician as by now I was getting a little irate) that if the other bike exhibited the same symptoms then I would have to accept that whatever we both thought of the forks they were actually working the way they were designed. I duly rode the replacement bike in exactly the same manner (with exactly the same pressure settings) and guess what? It behaved exactly the same!

The upshot of this whole exercise can be summed up as follows: The bike is entry level. They have put in a good motor and battery but have had to compromise in a big way in another area -- the suspension. What I have done, or rather not done, in buying this bike is to ensure that it was the right one for my riding style. The blurb says this is a go-anywhere bike and as I don't do any serious off-roading, just roads and trails, this might have seemed a good buy however it would seem that what I consider a trail and what Cube consider a trail are vastly different. I'm not going to change the bike, I may not even change the forks as now I know their shortcomings and know there is actually nothing wrong with them (except that they are a bit naff) I can live with them and their limitations.

I would expect that if someone bought this bike for road use with occasional forays onto unpaved cycle tracks they may not even notice that the forks are not very good and only if they hit serious rocks and potholes would they feel a little 'un-suspended'. If the road/cycle-trail experience is the way you ride then I can recommend this bike as it is effective and really quite comfortable and has an entry-level price. If you think for a minute you might occasionally try charging down a rocky dry stream bed then I strongly suggest putting in another £1500-£2000 for better parts (or get this bike and change the forks).

Anyway, for now, it'll do. I am enjoying riding it again, it is getting me much further for the same effort I would use on a non-ebike and that does make it a lot more fun. Whether at my age (68 in a couple of months) I'll ever upgrade remains to be seen but it's not likely.

Thanks for all your help on this matter but it is unfortunate that we were all trying to fix a fault that was never really there.

interesting read. i too love this bike and the you tube reviews are good. I've had a similar problem with my pro 625 size L (with x fusion mig air 32 100mm travel) purchased mid april 2022 it developed a "sticktion" . when i took it back for its first free service i explained this . it was duly lubed and the air pressure altered. since then it has got "stiffer" (ive tried various pressures and yes there is def. NO rebound adjust on bottom! ) . i recently took the bike back to the bike shop and they performed a lower fork service. the bike shop is still not happy with the outcome so they are sending the forks back to the uk distributor. i will see await the response.