Problem with Hope T-Rex 40t setup
I’ll offer up some of my thoughts:
– Worn Thick/Thin ring, on the left hand side, causing the chain to be pulled further to the right, and not retained.
– Chainline wrong – this isn’t the case, as the chainline further out on the exact same bike, but with the OneUp ring, is more than happy. Therefore, the chainline being actually worse on the other bike being fine, means that it should have nothing to do with the issue
– The ramping on the T-Rex ring is a bit odd – causing the dropping when back pedalling
Before anyone asks… I backpedal quite often on very steep big rocky step ups, at times – so that I don’t get pedal strikes, or so I can get my feet in the right place.
Any other ideas?Posted 3 years ago
I’ve just installed a Hope T-Rex on my 10sp setup. Indexing is fine, b-tension is good – the problem is the chainline. When back pedalling the chain drops two rings at the back.
The chain was a little noisy when pedalling normally, so I’ve popped in a very thin spacer behind the T-Rex, which resolves that – but the chain still drops when back pedalling a couple of gears.
My OneUpComponents 42t doesn’t do this, it’s absolutley fine back pedalling.
Anyone got any ideas? Or had this same problem? I am thinking of sticking a spacer on the BB to move the chain line – but I shouldn’t need to.
RicksPosted 3 years agoGolfChickMember
we had initial back pedalling problems on James’ but it was brand new chain so there was no lee way for imperfections. Since then the chain has worn in and it doesnt happen on either of ours. Have you tried mega slightly altering your b screw, I had back pedal issue for about five mins and I tweaked the b screw and it made it vanish.Posted 3 years ago
Yep, tweaked the B-Screw quite a bit, all the way out, and then just enough in so I get clearance. It is a new chain, well, two rides old – so possibly it’s a wearing in problem.
I didn’t have this issue with the OneUp ring though, which is what’s really confusing me.Posted 3 years agoNorthwindSubscriber
Mine is a OneUp rather than a Hope but tbh I didn’t have any of these issues. It was a total pain in the arse to get it set up right, lots of fannying about with the b-screw- I ended up sticking it on the turbo trainer and combining an intervals session with an indexing session 🙄 Just seemed to be a wee bit counterintuitivePosted 3 years agowolfensteinMember
😯 glad its not just me, i thought it’s me who doesn’t know how to setup gears anymore.. So common issue then.. I fitted 2 weeks ago a new KMC chain and dropping cogs whenever i slightly backpedal to prepare for an obstacle … And last week replaced the chain a slightly older used kmc chain from the other bike and all is smooth but wont engaged in my t-rex but it must be me didn’t fine tune re-indexing again when i replaced worn chain which doesn’t need to really 😐Posted 3 years agocraig_wMember
No issues here either. Set-up: New Sram Chain (1090), New Sram 11-36 X9.
I’ve started with a Hope thick/thin 30T on the front as I like to spin, but left a couple of extra links in the chain so I could move to a 32T if I felt this was too small. Maybe its the extra chain? Oh and its on an Alpine 160 if this helps.
The only other thing is that I’ve got an old knackered X9 rear mech. A bit of play in there might be helping.
CraigPosted 3 years ago
Mine will go down 3 rings if I backpedal. It doesn’t do it on the 36. I don’t think I’ll ever use it except when climbing and only backpedal on descents.
I wonder if the angle on the 30t causes the issue.
I had the same experience as Northwind with the OnUpComponents ring, works faultlessly but was a total pain to get setup right.
The Hope ring is easy peasy to index and get the right b tension, but back peddling causing derailment of the chain.
After initial set up it was dropping 3 rings, after one ride its down to dropping 1 ring.
Its not chain growth, and the chain length or the b tension won’t have anything to do with it, as those all have no affect in the top of the drivetrain, which is what is derailing when back peddling.
It must be tooth profile, affected by the angle of the smaller ring, and the lateral angle. I can see it sorting itself out once the rivets wear a little, so the plates can move laterally.Posted 3 years agochipMember
I fitted the same set up as chipbutty a couple of days ago, all new parts and new chain.
Mine drops two sprockets while back pedalling.
I tried adjusting the b screw despite not seeing how that could make any difference, which it did not, but I found if it was not wound in enough the chain would drop two sprockets then jam between the mech and cassette. I then tried using the supplied longer b screw and found if the b screw was screwed in too far it also jammed between the mech and cassette after dropping two sprockets.
So went back to the original screw screwed all the way in which was where I started.
The chain still dropped two sprockets but did not jam and climbed easily and quickly the moment you pedal forward.
I think this is due to tight tolerances in the new components and the narrow wide chainring which has very tight tolerances by design.
I really can’t see it being a problem as I don’t pedal backwoods accept for maybe when coasting behind some one slower while waiting for them to give way and defiantly not in a situation where I would be in such a low gear.
And if turning half a turn for pedal positioning I would always pedal forward.Posted 3 years ago
I also think as the drivetrain wears this will sort itself out anyway.dantiSubscriber
Anyone running an XT long cage clutch rear mech with the T Rex?
Would prefer to run what I’ve already got if possible (not sure whether a new chain comes with enough links to accomodate long cage and 32t chainring?).
If not I’m presuming a medium cage XT clutch mech will be ok?
ThanksPosted 3 years agodoombrainMember
Myself and a friend are having this issue.
Hope 32t retainer on SLX crank
XT long cage
Hope Pro2 hub
To me it’s a chain line thing, the angle is too aggressive off the chain ring. Maybe with time the wear will help smooth things out but i also find it a little too noisy therefore the wear will be high.
I’m going to try moving the 32t over to the frame by 2mm if i can find the right spacers and replacement bolts to take up the extra space.
I also dropped Hope an email, they are normally good at responding. May be they could knock up some CNCed spacers and bolts as a kit!Posted 3 years ago
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