- Advice needed on hollow tech bb and chain device issues
Right then chaps, I’ve fitted a Renthal Sr4 chainring and a ethirteen Lg1 chain device using a bb to Iscg05 adaptor ring, problem is in order for the chain ring to align with the jockey wheel on the chain device and not foul anywhere else on the device I’ve had to reverse the adaptor ring and use the thin shim washers and the original bb spacer, after about 4 hours of constant farting about and trying every conceivable combination, everything now works perfect exept that when I replace the non drive side crank arm it seems the axle comes through about 3mm short and therefore means the crank isn’t sat fully home and also the black plastic splined plug that threads in is no longer long enough.
Has anyone had this problem before or know how to rectify it? Do I need a to buy a bigger bb?
Thanks in advance for any help.
Thank you…… much lovePosted 7 years ago
Did you replace an existing spacer with the adaptor? And is anything fouling the crank?Posted 7 years ago
I took out the existing spacer and replaced it with the adaptor but I had to then reuse the spacer between the spider and the bb in order to stop any fouling and get everything aligned, I assume that reusing the spacer is what is causing the issue but it’s the only way it will work! Nothing fouls either crank.Posted 7 years ago
Something else doesn’t sound right… The wee plastic doobry normally has way more than 3mm of thread engaged, which means that if your crank is only sat out by 3mm it should still thread in. Unless I’m misunderstanding?
HT2 is designed to work with the recommended number of spacers but with my old SLX it worked happily enough with an extra spacer (I fitted too many by mistake one time!)Posted 7 years ago
I’ve just re checked that measurement and it’s more eight than three mm, sorry for the confusion 😳 .Posted 7 years ago
As I said the only parts on the drive side are (from frame outwards) adaptor ring, bearing race, approx 2mm spacer, crank arm spider. If that makes sense?
Have you given the drive side crank a good tap to drive it all the way through? It sometimes takes a bit of a thump to get it home- the extra 2mm spacer should only make a 2mm difference to the total width, so I suspect you have the crank sitting out of it’s slot by about 5mm. The plastic preload bolt should then engage and draw the rest of the axle through once you screw it into the LH crank arm, or draw the crank onto the axle. . . At the same time check to make sure you seat the left hand crank arm on as far as it will go. Have you lifted the little plastic security tab up and out of the way so it can slip on?
There is a suggestion that if you have used an extra spacer, you should have the opposite side of the BB shell refaced by the same amount in order to keep everything the designed width.Posted 7 years ago
Aye, sounds right to me too. You haven’t added 8mm of width so the crank shouldn’t be 8mm out.Posted 7 years ago
I’ll check when I get home, makes sense really but I’m sure it was all the way through!Posted 7 years ago
Forget the bit about refacing the BB shell, as you have the bearing cups in the right order, so the BB width will already be fine.Posted 7 years ago
I had to then reuse the spacer between the spider and the bb in order to stop any fouling and get everything aligned, I assume that reusing the spacer is what is causing the issue
Sounds like this is almost certainly your problem.
What was fouling without the extra spacer? The granny bolts and ISCG bolts?Posted 7 years ago
Right then, I’ve had a fresh look and basically I think the issue must lie with the re used spacer between the spider and bb race, basically the chain (on the chainring) was fouling inside the chain guard no matter how I arranged things until I put the spacer in, now it lines through perfect with the only issue being the one mentioned in the first post.
Also I cut the granny ring mounts on the spider down so there definitely isn’t any issues there.Posted 7 years ago
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