How long will your EMTB last you?

[Gary]

Not worked out how to measure BB. It seems quite variable depending on tyres, pressure, default sag for different riders.

Ideally you measure BB drop not height.
Drop is measured below (or above) wheel axle centre height so not dependant on tyre/wheel size

 

[Zimmerframe]

It's amazing how much you can learn with a bit of kiss and makeup ? ?

 

[Zimmerframe]

2kg

90kg.... ?

 

[Zimmerframe]

Ideally you measure BB drop not height.
Drop is measured below (or above) wheel axle centre height so not dependant on tyre/wheel size

Ok. I've had a ? and obviously being really dumb. How does that work ?

People say 28cm BB to middle of BB ? And you say drop ? But surely that would still be affected by individual suspension settings ? See dumb..

 

[Gary]

Normally both measured static (ie. unsagged f&r)
what beer?

 

[Zimmerframe]

Normally both measured static (ie. unsagged f&r)
what beer?

Ok. That makes sense now !

Presently going through a leffe, affligem and grimbergen phase.. ?

With Guinness on cooler days.. ?

 

[Pukmeister]

2kg?

I exaggerated with the 2kg figure but my point is that to improve strength in the crank area to absorb high forces means more metal, which means more weight. Wider bearings and housings means deeper cases and wider motors. This is the opposite of the design brief to keep making motors smaller and lighter than their predecessors. Its not just a simple case of buying better bearings for the job.

 

[Gary]

Its not just a simple case of buying better bearings for the job.

Yeah. I know that.
but seeing they weren't designed/spec'd suitably in the first place there's definitely room for improvement without adding anywhere near as much weight or enlarging the motor size by as much as you suggest.
Designing the motor with shop mechanic replaceable bearings and still retaining full warranty after changing them would actually have been my first preference.
it's a wear part FFS!

 

[Fivetones]

@Gary I’ve researched around this so yes I get that there’s play. At no point have I said that I think the design is suitable. Only that’s it’s understandable why they might have not got it right....yet. A line of thinking that doesn’t require me to wear a tin-foil hat ?

The rest of my thinking is above in previous posts.

@Pukmeister that’s really useful information. Thanks.

The obvious question then is: how can this be done for Shimano’s E9000 in 2021 where the requirement is 1. 2.2kg 2. 100nm 3. perhaps 20% more cost at most?

 

[Gary]

Understandable? Yes. Entirely
Forgiveable? Never

E9000 would make it XTR - this would not interest me.
E8200 now that would be SAINT it would obv be heavier. Everything SAINTLY is. but it might actually be durable enough for 1000+ miles
and if so I'd be a damn sight happier with half as frequent returns.

 

[Zimmerframe]

E8200 now that would be SAINT

So if I remember correctly, Simon Templar was the Saint .. he had a white XJS at one point, which people would also dream of it being durable enough to go 1000+ miles in.

Seems to me like we're just going round in the same circle.

What I don't get is, when you have a relatively finite failure rate, testing and repeating that failure, so you can fix it, can be incredibly difficult - this is pretty much the same for all the motor manufacturers, which I think (from keeping a rough track on here over several months) all have similar "ballpark" failure rates.

@Gary obviously has an incredible ability to consistently freck these things - so he should in theory be gold dust as a testing option. I'm surprised you've not been signed up by some brave company to destroy their products in the interest of advancement.

 

[Macone]

3500km on my focus Jam2 (Shimano E8000 motor) . Replaced chain 3 times, replaced Cassette, replaced Crank, replaced tyres and Brake Pads. Average ride around 40kms (some shorter, some longer). Conditions from hot dry and dusty to Cold wet and muddy. Average elevation gain per ride about 800m (some less some more). I weigh 115kg and use "Boost" quite a bit on the steeper stuff(so the motor has to work hard). no issues at all and am going for a 60k ride (approx 1100m climbing today). bike is 10 and a half months old. I didnt buy the bike to save money, just to have fun. I dont believe I am the "exception" here. I do believe that most of the owners who are happy with their bikes (and I firmly believe that we are the majority), just dont get on here and say much.

 

[Beekeeper]

90kg.... ?

If I give up my addictions to Magnum ice creams, I too, one day will be 90kg ??

 

[Beekeeper]

I’m thinking if I can get weight down from 100kg to 90kg it would boost range significantly? Also perhaps bike longevity. I’ve also got to compensate for the weight of this massive Abus U lock that has just arrived today. Wow it’s a weighty thing ?

 

[Pdoz]

@Gary obviously has an incredible ability to consistently freck these things - so he should in theory be gold dust as a testing option. I'm surprised you've not been signed up by some brave company to destroy their products in the interest of advancement.

My pet theory - Gary talks about riding up on the pedals all the time so he's putting a lot more rider load through the motors than the manufacturers expect. Imagine a highly qualified engineer sitting on his butt all day designing DRIVE units ( not weight bearing gymnastic equipment) . Perhaps taking offence when it's suggested his theory doesn't match reality ?

Now, can the engineers please step away from the computer, grab a chair at the bar and start drawing on some paper whilst sharing beers with the apes.....then go back and re write the textbook on emtb motor design.

Something simple, like stop trying to include the gymnastic equipment with the drive unit? ( ie motors seperate to cranks) ???

Frkit , switch those beers for something a bit stronger and start designing something even weirder than the fazua system?

 

[33red]

Being with 0 engineer knowledge i see other balls.
Lets say too many complain and Norco or some other want to divorce from Shimano.
They just cant. Their frames are made to mesure.
So this is a level of victim.
Let say a customer does not like the price of a Shimano motor.
Screwed again.
Let say her neighbor does not like the price to replace that Norco-Shimano battery.
All sign 2gether.
Screwed again.
Exactly like cellphone plans.
You are stuck.
They eliminate price shopping.
Some balls are in play

 

[Jamsxr]

I was in Pila earlier this year and the fleet of e8000 motors on the Merida hire bikes all had >1,500 miles are were all in good working order - we hired 6 of them for the day ?

 

[Macone]

I’m thinking if I can get weight down from 100kg to 90kg it would boost range significantly? Also perhaps bike longevity. I’ve also got to compensate for the weight of this massive Abus U lock that has just arrived today. Wow it’s a weighty thing ?

Yep weight seems to be the biggest factor in range variances between riders (but not the only factor), I sometimes ride with a mate who does about the same amount of riding as me with similar fitness levels. He however is much smaller and lighter (30kg difference). when we ride together, he gets almost the exact same range as me, with him using a 500wh battery and me having 756wh. Last couple of rides we have both ended up with 1 or 2km range remaining.

 

[HORSPWR]

Ok. That makes sense now !

Presently going through a leffe, affligem and grimbergen phase.. ?

With Guinness on cooler days.. ?

Aww you two are too cute!!

 

[Peaky Rider]

I was in Pila earlier this year and the fleet of e8000 motors on the Merida hire bikes all had >1,500 miles are were all in good working order - we hired 6 of them for the day ?

How many knackered ones were hiding in the shed out back?

I too was in love with my E8000 until a month ago, so much so that now it has let me down, I feel like a spurned lover and we know how bitter they can be.

 

[Fivetones]

I still have a question about lateral forces on the main bearing area. Wouldn’t these forces be absorbed mostly by flex in the rear wheel and swing arm/linkages?

 

[Gary]

clearly not

U even whip bro?

 

[Fivetones]

clearly not

U even whip bro?

Yeah but not at your level....yet ?

I’m just trying to figure out what could be the cause. For personal curiosity really but I think if collectively we had a better picture (based on various experiences) then that would be useful.

I’m loving my e8000 but inevitably it will fail.

 

[Gary]

Yeah. I love them too during that short window where they're not fucked!



Side loading of the axle is the cause. it's fairly simple to understand.
it doesn't just happed landing sideways. it happens every time you turn the bike. the harder you corner the more side load.

Go out and do a few cutties.. and think about what the crank axle is doing

 

[Fivetones]

The small spring loaded movement must amplify it.

I’d head out and try but I’m laid up at the moment.

 

[Zimmerframe]

This would be a lot easier if you simplied the world red33 style .. My E8000 had no problems in 1600km's. Therefore the E8000 is unbreakable. Therefore it's the best. Therefore every bike should have an E8000. Therefore anyone who says they've broken one must be incorrect (or doesn't exist).

Ok .. so lets say you had shorter cranks, that would ultimately reduce crank axle loading and extend longevity, reduce bending and force loading on the bearings. This is probably proportional. So for you next one, if you like it or not, you need shorter cranks. You are the ultimate test bed and you should be abused ! I'll send you mine if you like.

How about if someone knocked up a nice solid titanium bar which also fits perfectly inside the crank axle to improve strength/reduce flex/bearing compression.. If you were being really clever you could incorporate the crank end caps as part of this with threaded ends and different end caps They wouldnt' need to thread into the cranks, only sit in them as they do, but thread onto either end of the titanium insert.

 

[Gary]

Ok .. so lets say you had shorter cranks, that would ultimately reduce crank axle loading and extend longevity, reduce bending and force loading on the bearings. This is probably proportional. So for you next one, if you like it or not, you need shorter cranks. You are the ultimate test bed and you should be abused ! I'll send you mine if you like.

You sort of have a point... except...
Shorter cranks are fucking horrible. Sorry. I can't stress this enough. it's a mountainbike not a motorbike with foor pegs. weighting the thing is completely different to a motocrosser. All mtbs need to be able to be weighted heavily on the outside crank arm.
too short cranks are also horrible to pedal (especially if like me you also ride regular bikes every day).
too short and they also become pretty horrible to whip and table with and they reduce stability when cornering outside foot down.
Yeah. so other than thier extremely horribleness short cranks are a great idea.

Other than for springs titanium is a fucking stupid material to use on a bicycle. it's brittle stretchy cracky faily shite I intentionally try not to use on any bike of my own! Over a 30 yr period every single Ti bicycle product I've ever used has failed.
infact a few months back a riding friend let me have a quick shot on his tres expensive Ti Jones space frame fat/adventure bike thing.
I descended one short fast rocky fireroad. The frame cracked!
The only ti parts I use are Selle SLR Ti saddle rails (I love SLR saddles) but they also fail. (Two SLRs broken this year alone)

Axle stiffness in the E8000 isn't the issue.

 

[Fivetones]

Be honest, do you need to lay off the pies Gary? ?

 

[Zimmerframe]

Ok, so that's a no, NO and more NO... Unless I'm reading it wrong

My theory was that tiny amounts of axle flex would/could cause localised bearing pressures, leading to premature wear/collapse.. Re-enforcing the axle could be done to a degree without dismantling the motor, so if this led to a 50%-100% increase in longevity, it would be worth it... though it might not work at all.. in which case it wouldn't ....

Anything else you do requires the motor/motor housing to be re-designed - from what little I know about the motor... which it little with a capital L.

 

[Gary]

lay off the pies

Never.

TBF I broke far far more parts 20 years back when I was a svelte 12st, rode 200 miles a week and regularly raced DH.