Conversion kit advice for big/occasional MTB rider

[Frobisher]

Hi all,

Been reading this forum for a while and finally got around to posting. I think you need an "FAQ" in here as it's all getting repetitive, I know, sorry! Looking for a conversion kit for my existing full sus for offroad/trails (nothing serious).

I'm a tall (6'5") and heavy (110kg) rider and I've had knee and back issues over the years (in my mid fifties now) and have younger/fitter friends in the group so I often feel I'm holding them back on climbs. I feel a bit of hill assistance would help tremendously so they don't have to wait for me so much.

We tend to go to mountain bike centres like Llandegla, Coed Y Brenin, Forest of Dean and Cannock Chase so only 15-20km of climbing per day out. Gradients aren't insane but they're a struggle for me and I'm not going to get much fitter at my age.

I'm not interested in maxing out top speeds, I just want to have a bit of assistance for climbing without melting the battery. It's important that the bike handles as normally as possible when I'm not using the motor (i.e. on flats/minor hills/downhill). I want to be able to use the gears still, so it needs to be a mid-drive I think?

I very much want pedal assist. I have no interest in a throttle of any sort, would just like to be able to set the level of assistance as needed and have the bike help me out when pedaling uphill.

Having read this forum, it appears the BBS01 would do, but it's possible that other types should be on my radar too. I want to keep the costs down as I'm only an occasional user, but I feel that I may get out more if this can be done well.

Where I get confused in reading here is when I start seeing things about pedal sensors, brake sensors, etc. and I don't know if they even apply to torque/pedal sensing setups!

My bike is a 21.5" Calibre Bossnut:
Frame:Calibre aluminium, 130mm travel
Shock:RockShox Monarch R
Fork:RockShox Sektor Silver, 130mm travel
Wheels:Shimano Deore hubs, WTB Sti 23 rims, WTB Vigilante/BeeLine 27.5x2.3/2.2in tyres
Drivetrain:Shimano Deore chainset, mechs and shifters
Brakes:Shimano Deore, 180/160mm
Components:Ritchey 760mm bar and 70mm stem, WTB Volt saddle
Sizes:17.5, 19.5, 21.5in
Weight:14.5kg (31.97lb)
Head angle:66.1°
Seat angle:74°
BB height:342mm
Chainstay:436mm
Front centre:727mm
Wheelbase:1,163mm
Down tube:673mm
Top tube:595mm
Reach:433mm

 

[spanos]

I would agree that a bbsxx conversion would be a good fit for your bike, your weight and usage

With such a system there are no pedal sensors to fit- that's for hub motor setups

There are brake cutouts to fit and you'd need Hydraulic brake cutouts. These are a doddle to fit, simply fix a small magnet to your brake lever and cable tie the sensor to your bar. When you pull the lever the small magnet gets close to the sensor and activates it.

A bbsxx comes with nice, waterproof wiring connectors

You'll lose your front derailleur of course to be replaced by a single ring that comes with the bbs. (Alternative sizes can be bought if you need lower or higher gearing)

The hardest part of during the kit is removal of your old bottom bracket imho

 

[daveboy]

where are you ??? If you are anywhere near Pontefract you can come and have a look/ride on my BBSHD conversion I have just finished.

 

[Deleted member 4366]

You've left out the only important information: what type/size of BB do you have?

I just received one of these, but I haven't installed it yet. DHL duty etc. was £27, so you have to check the price difference with the no EU tax one:

http://www.pswpower.com/peng/iview.asp?KeyID=dtpic-2015-93-QDKT.6P4CE

 

[antenorareal]

I had a bbs and geared hub motor and I like more the hubs...with the bbs I feel that I does all the work for me and the hub I feel a little help, but I feel that my effort is felted. This is true for small and low powered hubs. And peddling without assistence is more natural.

Enviado do meu SM-G850F através de Tapatalk

 

[Frobisher]

Thanks for replies all. Away for a few days at the moment so hard to respond. Will catch up soon. How do I measure the bottom bracket then please?

Sent from my SM-G930F using Tapatalk

 

[Deleted member 4366]

You only need to measure the width (actually length) of the tube to see if its 68mm, 73mm or longer. next, you need to know how to recognise a press fit (PF) BB. Normal BBs have the dogs for a normal (Shimano type) BB removal tool. Most of the crank-drive kits are designed for 68mm Shimano type BBs, so it's very important to know which type you have.

 

[Frobisher]

You only need to measure the width (actually length) of the tube to see if its 68mm, 73mm or longer. next, you need to know how to recognise a press fit (PF) BB. Normal BBs have the dogs for a normal (Shimano type) BB removal tool. Most of the crank-drive kits are designed for 68mm Shimano type BBs, so it's very important to know which type you have.

Thanks, I'll take some pictures when I'm back home and hopefully you'll be able to point me in the right direction.

Sent from my SM-G930F using Tapatalk

 

[RobF]

Have you tried any eMTBs?

The conversion will dramatically alter the feel of your bike, which may, or may not, bother you.

I suggest you have a go on a pre-built full sus ebike to give you a general feel of what riding one is like.

It would be a bit cheeky trying a dealer's demo if you have no intention to buy, but you could always ask for p/ex on your bike - much to be said for a factory build over a conversion.

 

[Frobisher]

Hi all. According to specs, bottom bracket is a Shimano Hollowtech 68/73mm bottom bracket. I have no idea what this information means ;-)

@spanos The loss of the front rings was something I wasn't sure about, so thanks for clearing that up. The replacement is something that comes as one complete unit then with a replacement single crank? Does that mean I remove the front shifter lever as it's no longer needed? (not that I ever use it much to be honest - constantly on the smaller 26t one!)

@daveboy Thanks for the offer but I'm in the midlands!

@antenorareal I'm not sure that hub drive is best for me to be honest, but appreciate it works for other people.

@d8veh What is that PSW kit like then? Have you fitted it yet? I presume all I'd need to add to that would be a suitable 36v or 48v battery?

@RobF I have ridden a Trek e-MTB around a car park a few times as I hired it for my wife and couldn't resist a blast Not taken one near any up/downhill or bumps though. To be honest, having bought the current bike for £1k and being generally happy with it (but not my fitness or ability with it!) I think it would be too expensive to change to a decent full e-MTB instead of just spending £500 on a motor/battery. This way I can always sell the newly-converted bike in future or rebuild it as a manual one before selling it on then putting the electric kit on the next donor bike. Seems to give me more flexibility and I haven't got a massive budget to blow here. Resale value of my bike would be £500-600 at best.

Oh and the other concern I have is the strength of the new crank/pedals as my weight going through them on downhills hitting bumps at speed means there's a LOT of downforce on them... My "name conscious" mate is forever dropping disparaging remarks about cheap Chinese steel that will snap as soon as I hit a bump!

 

[Kos]

Hi all,

Been reading this forum for a while and finally got around to posting. I think you need an "FAQ" in here as it's all getting repetitive, I know, sorry! Looking for a conversion kit for my existing full sus for offroad/trails (nothing serious).

I'm a tall (6'5") and heavy (110kg) rider and I've had knee and back issues over the years (in my mid fifties now) and have younger/fitter friends in the group so I often feel I'm holding them back on climbs. I feel a bit of hill assistance would help tremendously so they don't have to wait for me so much.

We tend to go to mountain bike centres like Llandegla, Coed Y Brenin, Forest of Dean and Cannock Chase so only 15-20km of climbing per day out. Gradients aren't insane but they're a struggle for me and I'm not going to get much fitter at my age.

I'm not interested in maxing out top speeds, I just want to have a bit of assistance for climbing without melting the battery. It's important that the bike handles as normally as possible when I'm not using the motor (i.e. on flats/minor hills/downhill). I want to be able to use the gears still, so it needs to be a mid-drive I think?

I very much want pedal assist. I have no interest in a throttle of any sort, would just like to be able to set the level of assistance as needed and have the bike help me out when pedaling uphill.

Having read this forum, it appears the BBS01 would do, but it's possible that other types should be on my radar too. I want to keep the costs down as I'm only an occasional user, but I feel that I may get out more if this can be done well.

Where I get confused in reading here is when I start seeing things about pedal sensors, brake sensors, etc. and I don't know if they even apply to torque/pedal sensing setups!

My bike is a 21.5" Calibre Bossnut:
Frame:Calibre aluminium, 130mm travel
Shock:RockShox Monarch R
Fork:RockShox Sektor Silver, 130mm travel
Wheels:Shimano Deore hubs, WTB Sti 23 rims, WTB Vigilante/BeeLine 27.5x2.3/2.2in tyres
Drivetrain:Shimano Deore chainset, mechs and shifters
Brakes:Shimano Deore, 180/160mm
Components:Ritchey 760mm bar and 70mm stem, WTB Volt saddle
Sizes:17.5, 19.5, 21.5in
Weight:14.5kg (31.97lb)
Head angle:66.1°
Seat angle:74°
BB height:342mm
Chainstay:436mm
Front centre:727mm
Wheelbase:1,163mm
Down tube:673mm
Top tube:595mm
Reach:433mm

Having exactly the same setup and wanted to ask if you've got somewhere with converting it. I have an old Trek 3500 converted with front wheel motor, but really want my Bossnut Evo be ebiked with something close to 1000w system.

 

[Woosh]

If you want a more discreet conversion, I'd suggest the 48V SWX02 rear wheel kit.
http://wooshbikes.co.uk/?hubkits#swx02-48v-kit

 

[Frobisher]

Having exactly the same setup and wanted to ask if you've got somewhere with converting it. I have an old Trek 3500 converted with front wheel motor, but really want my Bossnut Evo be ebiked with something close to 1000w system.

Gave up on this idea long, long ago and bought a proper E-MTB! Didn't fancy trying to cope with the stresses and strains (on me or the bike!)