PAS sensor (KT-V12L) install issues
- Thread starter James Torr
- Start date
Ken when you remove the crank arm (pedal arm if you like ) the axle it sits on is part of the BB (Bottom Bracket) it is basically a shaft with a bearing on each side.
Remove the PAS and refit the crank arm tightly, measure the actual gap left. It should be 1 - 2mm greater then the PAS width.
With the pedal removed look directly in to the side cup and you should see some castellation's/crenulations, the V12L also has similar and these push firmly in to these to grip and prevent the actual PAS outer part rotating, the PAS inner part with small splines grip the BB axle then rotates freely when axle is rotated.
Sometimes the small splines brake off or don't grip the axle to well so if this is the case remove it and wind some black electrical tape or similar on to the axle then refit the PAS to grip better.
With the crank arm back in place there should be free air between the arms inner face and the PAS.
Remove the PAS and refit the crank arm tightly, measure the actual gap left. It should be 1 - 2mm greater then the PAS width.
With the pedal removed look directly in to the side cup and you should see some castellation's/crenulations, the V12L also has similar and these push firmly in to these to grip and prevent the actual PAS outer part rotating, the PAS inner part with small splines grip the BB axle then rotates freely when axle is rotated.
Sometimes the small splines brake off or don't grip the axle to well so if this is the case remove it and wind some black electrical tape or similar on to the axle then refit the PAS to grip better.
With the crank arm back in place there should be free air between the arms inner face and the PAS.
Yes, I ground down crank, which worked well for a year. PAS has worn down though and now I'm trying locktite (adhesive) to keep the bolt in place with hopefully the correct pressure on the PAS. There's got to be a better system!
Thank you for the photos! Yes I ground down crank for a better fit, which worked for a year only.
Unfortunately, changing the bottom bracket will solve one problem, but may give you one or two there issues to resolve!
If you are planning to use a longer bottom bracket to give you more space to install the sensor, this will push the front chainrings further away from the bike frame. You will therefore need to consider the chain line between the front chainrings and the rear freewheel cogs. Also, the front derailleur may not have the reach required to shift the chain to the outer ring.
I have tried changing the bottom bracket for a longer one in order to fit the PAS and always end up reverting to the original as gear changing becomes compromised.
Grinding cranks does the job, but it sounds a bit brutal!
If you are planning to use a longer bottom bracket to give you more space to install the sensor, this will push the front chainrings further away from the bike frame. You will therefore need to consider the chain line between the front chainrings and the rear freewheel cogs. Also, the front derailleur may not have the reach required to shift the chain to the outer ring.
I have tried changing the bottom bracket for a longer one in order to fit the PAS and always end up reverting to the original as gear changing becomes compromised.
Grinding cranks does the job, but it sounds a bit brutal!
if you replace the bottom bracket, in 4 times out of 5 cases, you go from 118mm spindle length to 122mm. The chain ring is moved out by 2mm requiring a simple adjustment for the front derailleur and you gain two new cartridge bearings.
Nealh, Thank you, thank you. It seems that, while my PAS worked for a year with no problem, the inner ring (with small spines) was being turned not by the axle, but by contact with the crank. I will need to build up the axle (with tape ?) so the inner ring is turned by the axle. Daaahhh!
I appreciate your, and all of the other responses, to my self-imposed dilemma. Thank all y'all.
This self amalgamating table is great for that purpose, its nice and rubbery and the splines in the PAS seem to grip it better than the normal black elec tape. ( actually my fav type of tape for many diy things as its not sticky but sticks to itself when stretched. - perfect for wrapping round connections for 100% waterproofing ):
https://www.toolstation.com/self-amalgamating-repair-tape/p23876
Installed new PAS (V12L - same as first one). Ground down crank more, nice fit, Spines turn with axle... but no peddle assist. I give up.
KT d12L if no ones suggested it... make sure you get the JULET connector read the yosepower kit thread from the beginning and it should answer many of your future questions or problems....
I can not find any UK stock and I just used my last one, with all the miles and road muck they only last about a year to 18 months but easy install and work as expected... I would say remove the back of the sensor and pop some poxy or hot melt glue in to waterproof it up a bit or use as is if it's well sealed when/if you get it.
ebay (china) Kt d12l
aliexpress (China) Kt d12L the seller I purchased off
I can not find any UK stock and I just used my last one, with all the miles and road muck they only last about a year to 18 months but easy install and work as expected... I would say remove the back of the sensor and pop some poxy or hot melt glue in to waterproof it up a bit or use as is if it's well sealed when/if you get it.
ebay (china) Kt d12l
aliexpress (China) Kt d12L the seller I purchased off
When I tried to fit the KTV12L to my wife's trike it was apparent there was not enough room on the left hand side, and the 'old fashioned' bottom bracket had no spline holes to catch the sensor housing. In any case the sensor and housing was way too wide, to fit between the pedal and the frame.
I went back to yose and they sold me a 2 piece sensor (you can get them a lot cheaper on ebay), but even then it needed a dremmel to make the disk thin enough, hot melt glue to fix it to the pedal and a 3mm shim between the sensor and its supporting bracket, but now works a treat. If it starts causing problems, then I may swap it to the RHS and glue the disk to the chain ring.
The centre grip on the sensors is quite flimsy and if the disk sticks for any reason, the rotating crank wears the centre down and it doesn't work anymore, hence the hot melt glue.
I suspect that if you have space on the crank, and a bottom bracket that fits the sensor, it is a good solution, otherwise my advice would be to forget the v12L and just get a 2 piece sensor.
I went back to yose and they sold me a 2 piece sensor (you can get them a lot cheaper on ebay), but even then it needed a dremmel to make the disk thin enough, hot melt glue to fix it to the pedal and a 3mm shim between the sensor and its supporting bracket, but now works a treat. If it starts causing problems, then I may swap it to the RHS and glue the disk to the chain ring.
The centre grip on the sensors is quite flimsy and if the disk sticks for any reason, the rotating crank wears the centre down and it doesn't work anymore, hence the hot melt glue.
I suspect that if you have space on the crank, and a bottom bracket that fits the sensor, it is a good solution, otherwise my advice would be to forget the v12L and just get a 2 piece sensor.