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Set screws rear dropouts
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A parts question. I have had to replace the set screw on the drive side twice over the first year with my small QR PR6. I think it may be caused by the Neo trainer and the smaller frame or perhaps it is bad luck. Are these adjustment screws easily purchased at any Home Depot? It does not appear to be very specific. I want to be ready for the next time this happens so that I am not at the mercy of the shop. Thanks.
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Re: Set screws rear dropouts [lyla] [ In reply to ]
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I'm guessing you mean the 2 part bolt/nut set that holds the hanger to the derailleur? My other guesses are the b screw adjuster that's part of the derailleur or what is normally 2 bolts that hold the hanger to the frame.

If it's the fastener there are a few different sizes. Sometimes you get them with a spare hanger, which is worth having anyway so that's something to check. If not they are very cheap online. Maybe fire a question to QR or measure the ones you've got. But this sort of thing? The same website has other sizes.

The b screw is part of the derailleur so you'd check the model to be precisely sure but something like this should do it.

If it's the hanger to frame bolts they are the most normal of the screws but maybe more possibilities. I think they are less likely to come with a spare hanger but still worth checking. Or, again, fire a question to QR or measure the ones you've got. But, very broadly, like this?

I'd get from a website just because it's so easy to find stuff once to know the measurements and a few bolts through the letter box is very convenient. I got a great deal on an expensive time trial shifter set because the shop had lost a bolt. Replace the bolt for next to nothing and used ever since. Hope that helps.
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Re: Set screws rear dropouts [OddSlug] [ In reply to ]
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OddSlug wrote:
I'm guessing you mean the 2 part bolt/nut set that holds the hanger to the derailleur? My other guesses are the b screw adjuster that's part of the derailleur or what is normally 2 bolts that hold the hanger to the frame.

I believe he/she means the horizontal dropout adjustment screws:


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Re: Set screws rear dropouts [lyla] [ In reply to ]
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If it's the horizontal dropout screws as per the picture above, the solution is to REALLY crank down the tightness of the rear skewer. If the skewer is only 'moderately tight', when you thrown down big watts, say on a climb or sprint, the wheel slides forward and then those wimpy screws are the only thing holding back the wheel - they will almost invariably be stripped and pushed back into the frame as a result. (Or broken).

You have to tighten the rear skewer so much that there is zero chance of slippage. I literally had to buy a new skewer to do this after multiple failures on normal skewers - the Dura-Ace rear skewer I bought (awhile back though) has a large handle so you can really crank it down hard.

Replacing those screws is really annoying as well - on my Cervelo P2c, I had to buy small screws and washers and then use 2 washers to hold it in place like a sandwich since I had stripped the threads completely.

I hate the design, but it is what it is.
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Re: Set screws rear dropouts [lightheir] [ In reply to ]
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That is correct. The set screws are just a convenience to help line things up before tightening the skewer. They should bear no load at all.
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Re: Set screws rear dropouts [lyla] [ In reply to ]
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Yes, they are common hardware. Take one to ACE or LOWES and they will be able to match it. The first time I had my rear wheel off, I noticed how easy mine turned. I put some Loctite thread-lock on mine, and they haven't moved since.

Athlinks / Strava
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Re: Set screws rear dropouts [lightheir] [ In reply to ]
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lightheir wrote:

You have to tighten the rear skewer so much that there is zero chance of slippage. I literally had to buy a new skewer to do this after multiple failures on normal skewers - the Dura-Ace rear skewer I bought (awhile back though) has a large handle so you can really crank it down hard.

Good advice to a point, but depending on your wheel then you need to be fractionally cautious of putting too much side loads on the bearings. I appreciate the advice here is in the context of a neo trainer, but just in case anyone reading doesn't have the full mechanical know how, then thought I'd warn incase they got all medieval on a QR lever and crushed the bearings. Having said that I had an old set of zipp 101s where if I didn't put sufficient side load on from the skewer the wheel would have slightly too much play - the bearing pressure was set to assume that additional push from the QR skewer.
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Re: Set screws rear dropouts [Duncan74] [ In reply to ]
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I see your point, but honestly, I've been horrified with how much force is required for me to keep my rear wheel in place (not on a trainer, but on big climbs). If I don't make it as near maximally tight with that Dura Ace beefy skewer, it's not enough, and the wheel slips when I'm doing sprints or hard short climb segments. It's possible I'm damaging some bearings I guess, but I don't see any way around it as it royally sucks when your wheel suddenly sucks forward into your frame on one of those hard efforts.
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Re: Set screws rear dropouts [lightheir] [ In reply to ]
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Really odd. I've had a skewer go on me to the point that it lost the 'grip' and would work loose, but that was after 10 years. And in the past I've been 100kg and putting out 1400watts when sprinting and never had any issues with wheel slip. Wheelspin, yes, and frame flexing, but not the axle moving.

I'd have thought the back force from braking would be more of an issue than the forward force from the chain when climbing, if for no other reason than the moment of that force is so much greater.

What's the surface of the QR skewer like? Is it smooth or is there a grooved pattern to it? Just wondering if you're missing a washer of some sort. Note I'm just keen to help here, as something is not sounding quite right. Not arguing at all or trying to send you on a goose chase.
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Re: Set screws rear dropouts [trail] [ In reply to ]
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Thank you. Yes, these are what I meant. Saw this kit on QR's website as well.
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Re: Set screws rear dropouts [lightheir] [ In reply to ]
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Thank you for the reply. Both times it has occurred it has thrown off the rear wheel completely and nothing moves. I will look for back up screws and make sure the skewer is tighter but not medieval tight.
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Re: Set screws rear dropouts [Duncan74] [ In reply to ]
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I use the skewer that came with the Neo and the skewer that came with the Ardennes when I'm training. It makes sense to start with being aware of how tight or loose the wheel is or how much wiggle I have on the trainer. Thank you.
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Re: Set screws rear dropouts [lyla] [ In reply to ]
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I had much the same thing happen on my P2C.
Yes, the set screws can be purchased at Lowe's. I think I got a pack of 10 for like $3. No big deal.
Also agree on a little Loctite on the threads. Be careful- go with blue or purple Loctite, not red. Red requires heat and more torque than those little screws can handle to disassemble.
If you ever change tire size or seat a different wheel, you'll need to adjust the depth of the rear wheel, so permanently bonding them in place may be a bad idea.

I also found that torquing down the rear skewer really tight helps. Everyone is right that those set screws are in no way load bearing. I bought these:
https://www.amazon.com/...ocking/dp/B077XZ8FDK

You can torque them down really tight, they have an good inside texture that can "bite" into the frame, and they seem to be working. Just remember to keep the little key with you or a 5mm allen key.
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Re: Set screws rear dropouts [lyla] [ In reply to ]
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I have a CD0.1 and have had the same issue with my QR. I couple things I do now.


1)Be careful when changing the rear wheel out and going to a direct drive trainer. Just make sure you aren't slamming it in there so they can bend.
2)Make sure I've lubed the screws up before putting them in. If you can't get them out you have to get a whole new hanger.
3)If getting the hanger package and swapping, make sure you you put some grease on the bolts so you can get them out.
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