Got my new 2023 SC, and I have a weird issue.
Taking the back wheel On and Off does NOT seem right - it interferes bad with the top pulley wheel due to clearance issue

What am I missing, or is this a frame/derailleur hanger design issue (or manufacturing issue on a component)?

Details:
- Medium frame
- Shimano 12 speed (Ultegra derailleur)
- Standard Pro 51 Bontrager wheel, 25 mm Conti 5000 tire

I am going into the smallest cog in the back.
At first the wheel comes out nice.. Derailleur swings back smoothly till it reaches the end stop.
but you reach a point where the small cog with the chain binds completely to pass the top pulley wheel. Puts pressure on the derailleur (it can't swing back further, hard stop) and it starts deflecting.
On the front, the 25 mm tire is jammed in the widest part of the opening (problem would be worse with a 28mm tire!)

Only way to remove is put more force, bends the derailleur assembly and what it is attached too slightly then it releases...

Note: Normally I do hold the read derailleur w one hand, rotating it all the way back too to help, but in below picture I needed a hand to take the picture - still the RD is rotated as far back as it will, hard stop.



But in this process, the inside of the derailleur cage also gets stuck between 2 cogs, scratching it (paint all scratched up from taking the wheel off 2-3 times only!);



I checked the derailleur hanger - it had a little of play (maybe from taking the wheel OFF and On a couple of times!); I tightened again (and found out the 2 mini screws had the hex stripped or about to..

The problem would be avoided (or be less) if the Shimano bracket was not resting on the stopper of the hanger (green box above) and instead tightened while being rotated back a bit (yellow arrow) but checking the Shimano manual - and common sense) - the correct way to install is resting on the stop of the hanger.

Only other way I see, is deflating the tire every time - but if working with tubeless, I assuming that replacing the air each time would make the sealant go bad a lot quicker... I originally thought I would run this bike w 28mm on the rear, at least in training - especially with the 23mm internal width stock wheels - but the situation above alone is a reason to not go higher than 23mm tires.

What am I misssing? Or am I not the only one? Can't imagine it is supposed to be like that. I do not have this issue on my older 11 speed Madone with 8000 RD.
Hoping it's something stupid..

---

---------------------------------
T. Guertin / Spocket

Check the B-Screw setting and pulley clearance? My wife’s came from the shop without enough tension. Still have issues threading in the rear thru-axle which is something I haven’t run across before.

I have alignment issues on that rear dropout with screwing the rear thru axle in, too! It’s pretty frustrating.

The B-screw alignment screw affects how far forward the derailleur can come (so affects the range of rotation in the other direction).
When the derailleur swings back "out of the way" the end stop is given by the Shimano bracket that is required when the bike does not have a direct-mount hanger..

---

---------------------------------
T. Guertin / Spocket

is the clearance just on the sides or do you have clearance on the downtube? On my current bike I can ride a 28mm front with fork side/top clearance but due do to the increase "depth" of bigger tire the tire rubs on the on the downtube on certain road conditions.

thanks.

Well, for reference if someone else read the threads and have an issue with clearance removing the rear wheel such as my post above..
- Trek support was not useful
- Interestingly enough, the part number for the derailleur hanger says "improved version for clearance with 12 speed drivetrains" - but clearly the change was not large enough on some frames

I talked to a mechanic. He says he's seen that several times with the newer 12 speed drivetrains. Only 2 solutions, neither elegant:
- When you remove the rear wheel, first losen up the screw holding the RD on the hanger, rotate the RD back a bit, then tighten again. Then proceed w normal removal, when re-installed, set back the RD in correct position. Actually not bad to do, only takes less than a minute more. Just a habit to take (must not forget to put back at the last step though!)

- Or grind the Shimano knuckle a bit, to allow for more rotation range.(

I ended up grinding the knuckle a bit on the bench grinder and putting a layer of black spray paint back on it afterwards. I have good clearance now.

For the alignment of the skewer, see my next post..

---

---------------------------------
T. Guertin / Spocket

For the issue with the alignment on the rear dropout when screwing the thru axle, I ran into that yesterday when working on the fix for the RD clearance with the wheel removal.

It's an easy fix.. the root cause is simply the derailleur hanger set off-axis with the axis of the thru axle. The thru axle goes through it before reaching the threads in the frame, and if off-axis, it simply makes things difficult.

Fix:
- ideally put bike upside down to make it easier
- loosen thru axle and pull out a bit
- CAREFULLY loosen the 2 small 3mm screws holding the RD hanger so that it can wiggle a bit
- Re-insert the thru axle in the treads (you might have to wiggle a bit, but should go in easy without the hanger guiding it off axis and go most of the way in
---> this also sets the hanger on the correct axis
- CAREFULLY tighten the 2 small screws of the hanger back so it is set in the correct axis
- Test removal and install of the thru axle - should go in and out easy now..

I said "carefully" about the 2 screws.. they are SUPER easy to strip the small Allen wrench tool in the head. Might be a good idea to have extras on hand. They are M3x12mm countersunk screws. You can get from Trek or Amazon. I had to replace mine, one was stripped when I received the bike it seems, the other one was going.

---

---------------------------------
T. Guertin / Spocket

Thanks for the follow-up. I am in Kona now and was able to check my wife's SC cassette clearance from the open RD. Her's opens up just enough that the chain is slightly past vertical.

I noticed the improved clearance hanger offering too, as I picked up an extra for traveling with the bike.

Online I saw the b-knuckle grinding solution. There was also info on the Team Ineos fix being to rotate the knuckle slightly clockwise to provide more cassette cog clearance and then tightening it down. This fix wouldn't be great for the long term as it doesn't take much to slip the knuckle.

Thanks for this follow up too. I tried loosening and resetting the hanger first thing and it helped a little. I'll do it again with your approach and some more precision as the thru-axle not starting easily is pretty frustrating!

Stumbled across these on the trek website.

https://www.trekbikes.com/...958/?colorCode=black

Sweet Fancy Moses. $3500??

Wonder if these will make it to the shores of Aus. But yeh, ouch, the price. I see they have rounded end ones too, the ones pictured must be for sram blips? Thats a lot of coin to dump into a bike. I wish Mitch was still around for any details?

This is all incredibly validating to hear. I have been facing this issue and always suspected it was my fault for using OSPWs.

Do you have a photo of your fix, I'd love to copy you, I'm currently using the "loosen and retighten every time" method, and that is getting old.

---

~Zac

Likely playing UCI production availability games so they can equip team riders in-house. FSA/ Vision did this with the Cervelo P5 riser/extensions carbon combo Jumbo-Visma and other teams are using. About the same price range as Trek too:(

Would taking the chain off help anything or is it purely the rear der. Issue?

Purely the rear mech. Chain doesn't help for me.

---

~Zac

That sucks. I came close to getting a new SC, but bailed due to the cost...and that was with a 30% off discount. It's a shame a new frame is impacted by something like this...I would be pissed if my frame/paint was damaged due to this issue-which seems it has happened to another poster.

I email my LBS still not heard back. Not sure if trek is making these custom? Garmin mount? Water bottle? Lot of unknown.

---

2024: Bevoman, Galveston, Alcatraz, Marble Falls, Santa Cruz

They are probably custom parts for a UCI team. They have to make them generally available to be able to use them legally. The usual way around it is to make them available for sale at a ridiculous price which no one will afford to pay.

---

What's your CdA?

3500 does not seem awful. Speedbar is more, Wattshop is a little under.

---

2024: Bevoman, Galveston, Alcatraz, Marble Falls, Santa Cruz

Worst part of the bike. I have not found a fix.

---

2024: Bevoman, Galveston, Alcatraz, Marble Falls, Santa Cruz

I've built up 6 of the new Speed Concepts (5 were Shimano 12-speed and one was Shimano 11-speed, 4 were medium, one was a small and one was a large, all the mediums were 28mm tires) and have not seen this in any of the bikes. I am very interested to understand what is going on!

Since mine is re-mounted and painted, there is not much to see unless you would have another one side-by-side but below represent what I did on my Ultegra 8150 knuckle to solve the issue. At first by looking at how the knuckle interacted with the RD, I thought that cutting the corner (yellow line) of the sharp point on the bench grinder would be enough to open the range of rotation backwards.. but by trial and error I found out I needed to grind a bit lower and behind of it - see the red line with the kink (approximated path.. try to remove as little as possible).

I seem to have plenty of clearance now. I just cleaned, masked the non-ground area and spray painted black again so visually you cannot see anything.

Note: searching for a picture of the knuckle to do the below image, I saw the Dura-Ace knuckle has a hole in the meat of the material in this area, as weight reducing measure. So grinding this down might not be ideal.. In that case buying a 8150 knuckle to modify is likely better. Seems like a $15-20$ part at least used on Ebay (this knuckle is removed for frames/hangers with a direct mount RD setup). I assume they are the same shape otherwise.

---

---------------------------------
T. Guertin / Spocket

Only because you haven't let me make you something. :P

Many many thanks to all those who have posted on this thread. Been great reading through from start to finish.

So I think I am close to pulling the trigger on a new Speed Concept. Will be my first Trek of any sort after a life of various Cannondales, Giant and my current Argon E-114. Yes, that's right I'm still riding an E-114. My main focus is full IM, although as I'm getting older may have to drop to half for injury prevention. I'm FMOP rider with my IM times just a few minutes over 5hrs on the Argon with the mighty SRAM 80s ;-) Note that I'm just a stereotypically tight yorkshireman - I hate to see waste and it takes me a very very long time to feel I've the value out of a purchase, so I tend to buy after way way too much research and then keep for years. That said, I am in a fortunate position that budget isn't one of the constraints on purchase.

So after years of E-114, then my heart was heading to the E-119 disc, but my head is saying Speed Concept for the reason that the stability is rated so highly. There's some specific issues I have, firstly I'm tall, but all in the legs, so I sit really high on the saddle and so have a high CoG, and I've a slight neuro issue that means my control for speed wobbles/gusts is not the best (please don't ask me about the SRAM80 front.....).

Fit: Saddle height to rail is 780mm, Pad X-487, Pad Y = 675. Note this gives me a big drop despite the relatively high Y.

Based on all of this then I think that the Large size puts me right in the sweet spot of the adjustments and if I read right then if I go for an 'off the shelf' then that will come with the mid stack/reach and long seatpost I need. So no real advantage to a Project one?

My final 'issue' is that I'm a lifelong Quarq fanboy, have 3 now and love the support and 'just work' nature of them. That said I am also a shimano groupset-a-holic - had SRAM on my Specialised Epic MTB and whilst noting this isn't fair reflection, would like to go Shimano on the new bike, but clearly won't be going Shimano for power meter. So that then means swapping to a AXS/Quarq powermeter with the rest of the setup shimano, or going Vector pedals which probably makes more sense.

So confirming questions - is the large the right size and am I correct in reading the fit guide that the supplied parts are right for me? And any thoughts on powermeter. At the moment the decision on the SC6 vs SC9 is based just on availability.

Edit to add one more question. Noting I'm currently limited to 23mm max on the Argon which isn't fun on rough chipseal, is the clearance really only 25mm on the front, or is that dependent on the rim width? Ie if I were to get a wider rim would a 28 fit? NZ loves rough chipseal, so it's a consideration.