Scott RC 10 Carbon Fibre MTB conversion - sensible or not?

[Revoli]

Hi. I am new to the world of electric bikes. I have a range of ordinary bikes as I used to be a fanatical cyclist. I now have a heart problem that means I am not supposed to do any voluntary exercise. Need to restore my sanity and find a way to get back on two wheels. Conversion is my first thought, the Scott mountain bike being the first contender. Basically one of these. http://www.mtbr.com/cat/bikes/xc-suspensio/scott/genius-rc-10/prd_412995_1526crx.aspx
Carbon fibre frame, hydraulic brakes, weird geometry etc. A joy to ride but can I convert? A bottom bracket conversion is I suspect out. Front wheel would unbalance the whole thing and get no traction so rear wheel? 9 speed sis shimano bloc. That looks like a problem? Does anyone have any experience of converting high end (old) mountain bikes or is this a folly? Will the conversion kits get me around say a 20 mile off road circuit (moderate terrain). I can pedal flats in moderation but hills are out without some help. My kids are getting fed up of being tethered to my bike to pull me along. I think the whip was the killer.

Or should I just accept I have to stick with roads now and buy a hybrid bike and sell off my treasured two wheeled chums?

I also have a Brompton and a 35 year old superb Team Raleigh 531 road bike with lots of nice campagnolo bits. I could do one of those and have seen the Brompton kits which look good if a tad pricey. I would welcome any ideas or thoughts.

 

[Deleted member 4366]

What bottom bracket does it have? You can buy adapters for some, otherwise yoy have to make them yourself.

 

[Revoli]

What bottom bracket does it have? You can buy adapters for some, otherwise yoy have to make them yourself.

It's a shimano xtr, so splined cranks. 73mm diameter I believe. Can you mount these things on Carbon frames?


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[nemesis]

I fitted a bafang crank motor to a Whyte carbon bike a few years ago and it was great.The main thing is that carbon frames are oversize around the bottom bracket area for rigidity so it may not go in.Mine only just did.

 

[Revoli]

I fitted a bafang crank motor to a Whyte carbon bike a few years ago and it was great.The main thing is that carbon frames are oversize around the bottom bracket area for rigidity so it may not go in.Mine only just did.

Interesting. Can you tell me more. Why will they not fit? Did it get you up hills ok and did it survive muddy conditions. I m not sure if these things have IP (?) water testing certification or something equivalent. I worry that in that position a motor is really exposed to everything. If I am going to do it I want a very robust conversion. A rear wheel motor would presumably be better protected but they seem out of favour - or is that just the manufacturers persuading us to buy mega expensive new bikes??


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[nemesis]

Interesting. Can you tell me more. Why will they not fit? Did it get you up hills ok and did it survive muddy conditions. I m not sure if these things have IP (?) water testing certification or something equivalent. I worry that in that position a motor is really exposed to everything. If I am going to do it I want a very robust conversion. A rear wheel motor would presumably be better protected but they seem out of favour - or is that just the manufacturers persuading us to buy mega expensive new bikes??


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The best mid drive is the Bafang BBSHD, if you go on EM3ev`s website there is a lot of information about fitting and also good info about what batteries to use.
Youtube is a good place to have a look how they perform.

 

[Deleted member 4366]

You still haven't given enough info about the BB. There's lots of different typed of XTR. Is it press fit or threaded? Most are press fit in CF frames. I'd be surprised if it's 83mm. They're normally wider in a CF frame. Pleas give exact details if you want guidance on how to fit a BBSxx motor. You can have a look at this in the meantime:

http://www.pedelecs.co.uk/forum/threads/my-latest-and-most-difficult-conversion-trek-top-fuel-9-9-carbon.25097/

 

[Revoli]

You still haven't given enough info about the BB. There's lots of different typed of XTR. Is it press fit or threaded? Most are press fit in CF frames. I'd be surprised if it's 83mm. They're normally wider in a CF frame. Pleas give exact details if you want guidance on how to fit a BBSxx motor. You can have a look at this in the meantime:

http://www.pedelecs.co.uk/forum/threads/my-latest-and-most-difficult-conversion-trek-top-fuel-9-9-carbon.25097/

It's the XTR FC-M960 Hollowtech II. BB is 73 mm wide. One of these is what is currently in there:
http://www.bikedrivetrainmall.com/shimano-fc-m960-xtr-complete-bottom-bracket-assembly-english-6873mm-b000al58v0




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[Deleted member 4366]

That shows a screw thread. How have you got a screw thread in carbon fibre? Are there moulded in inserts or something else?

"Because of this technology we're able to improve pedaling stiffness some 10% on some of our frames, over traditional threaded bottom brackets," says Giant global marketing director Andrew Juskaitis. "[PF86/92 is] less subject to tolerances, too, and is able to take up +/- 0.5mm of [shell width] discrepancy."

Scott US marketing and PR director Adrian Montgomery touts similar reasons for his company choosing BB86/92 over other standards:

 

[Revoli]

That shows a screw thread. How have you got a screw thread in carbon fibre? Are there moulded in inserts or something else?

"Because of this technology we're able to improve pedaling stiffness some 10% on some of our frames, over traditional threaded bottom brackets," says Giant global marketing director Andrew Juskaitis. "[PF86/92 is] less subject to tolerances, too, and is able to take up +/- 0.5mm of [shell width] discrepancy."

Scott US marketing and PR director Adrian Montgomery touts similar reasons for his company choosing BB86/92 over other standards:

It's a screw thread. Haven't had it apart for a while and cannot be sure if thread is in Carbon. I don't recall an insert and remember wondering about it at the time. There are very specific torque settings throughout on this bike. Carbon would be okay with normal pedals but for a high torque motor...... needs checking. You've got ,e thinking on that now. Good thing.


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[Deleted member 4366]

It's very important to identify exactly which bottom bracket you have, so that you can select the right motor and determine which adapters you'll need. What you've said so far doesn't sound right to me.

It takes about 5 minutes to take off the cranks, and then you have the answer much quicker than the time it's taken to write all this. With the cranks off, you then need to measure the width of the BB. I'll be very surprised if it's not more than 83mm, in which case you need the 100mm BBSxx.

 

[Revoli]

It's very important to identify exactly which bottom bracket you have, so that you can select the right motor and determine which adapters you'll need. What you've said so far doesn't sound right to me.

It takes about 5 minutes to take off the cranks, and then you have the answer much quicker than the time it's taken to write all this. With the cranks off, you then need to measure the width of the BB. I'll be very surprised if it's not more than 83mm, in which case you need the 100mm BBSxx.

Thanks for the response but it's 73mm measured with vernier and confirmed in manuals.

The reason I am getting electric bike is coz I am recently disabled. What used to take 5 mins takes a hell of a lot longer but I get your point. I have to plan anything carefully these days. You have made me think about the forces involved here though. A motor with some decent torque is going to need some holding. There are a couple of suspension mount points nearby which could probably take a stainless steel plate with a bit of careful work. Am I being a numpty here and just starting with the wrong donor bike? Would I be better off selling the super light carbon fibre Scott with full XTR groupset and either buying another or using my old hardtail Scott alloy bike as the starting point. Drilling holes or welding that one I don't have a problem with. The RC10 is so nice it seems a shame to trash it and make it super heavy. I think I will work up plans on both and see which looks better on paper. The idea of being able to ride my full suspension bike again is very appealing though..... All input gratefully received.


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