Mechanics and Fixing Any Questions Answered

Will 28mm tyres wind up being 'narrower' than 25mm tyres on a 27.5mm ext rim because less light bulb shape? Wider/narrower/the same? I'm getting a tiny bit of wheel rub when the rim flexes under load - so if I can shave a mm or two it would be useful. I know different tyres come up with more difference than that anyway so if I'm on a hiding to nowhere that's fine.

I have this jump bike rear wheel. The 8spd chain I’m trying to fit is slipping all over the place, I can barely turn the cranks with the bike in the stand, although the chainline is good. I really don’t want to spend much money on this so if anyone has spares or can recommend an easy fix please let me know.

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Looks like you need a 1/8 (track, bmx etc.) chain for that sprocket?

are they shorter between pins? i don’t not believe you but want to understand why. btw i don’t think this chain is hideously stretched

Anyone got a spare i can try out in or near camberwell?

In Nunhead. Let me have a rummage and see what I can find. Won't be until tomorrow if you can wait that long.

https://velodrome.org/wp-content/uploads/2016/02/FATQ_road_v_track.pdf
I know we all love a pdf.

yes please, let me dm you, thanks

twas informative (and not too long)
what chain rings do Halo expect given this is an mtb?

A lot of more jumpy bikes borrow a lot of BMX parts, but you'll be pleased to know you'll be fine running an 1/8th chain on a 3/32 chainring, not sure if it'd be a bit noisy on a narrow/wide one or just ineffective, but as it's singlespeed the N/W isn't necessary, just what lots of single rings are now.

I might have a KMC single speed chain in the garage

thank you! good to hear about the chain ring too. can’t believe i didn’t clock it might need a different chain, isn’t this a single speed forum?! who am i? length is not going to be an issue- it’s a 14” bike running 26/11t gears

isn’t this a single speed forum?!

I did think such thoughts.

Just tried to replace the rt99 rotors on my red etap 22 calipers with XT 800 ones, and I can't stop them rubbing. It's only very light but enough you can hear it. I suspect it's just that they're too thick, so my question is this - apart from the spenny SRAM ones, are there any good centerlock rotor options which are thinner than the Shimano ones (like the SRAM ones are)?

Unlikely.

I've seen a GP Urban 35mm come up 34mm on a 'not massive' road rim but most tyres I use are true to size or bigger.

Rotors should be about the same width I think. You need to open pistons fully and center it very carefully, not a lot of clearance with these brakes when all is new

It's fine with a worn (1.6mm) Shimano rotor, just not a new one. They do all appear to be about 1.8 new though. Will swap the pads and see if that helps. Wonder if the spring isn't pushing the pistons back enough/opening the pads enough. It's a very, very slight rub so must just be catching.

Try to open bleed ports at lever and open pistons, sometimes they're overfilled. Check the rotor is perfectly straight, sometimes they aren't even when new. The spring does a lot of noise if badly installed.
You can also try to play with the reach, less reach = more travel and less rub

You can also try to play with the reach, less reach = more travel and less rub

Elaborate if you may pls?

Suspect they mean the contact point adjustment you can do on red levers. I'll have a play later on. May just need to lube my pistons...

Anyone ever managed to crack a decent forged crank arm? Fitted my lovely TA Zephyr cranks to a build, and on the NDS I didn’t even get close to 40Nm before it gave out around the bolt. How did I fuck up?

May give Chicken a call but as I’m not the original owner can only assume any warranty would be moot, even if this would count for it.

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How did I fuck up?

You didn't, that's just where you'd expect a square taper crank to fail. If you take it apart, you'll probably be able to see the fatigue crack which has built up over a long time which reduced the intact cross section enough to allow a brittle fracture of the remainder as you pushed it up the taper. If you hadn't broken it now, it would have gone at the worst possible time while riding, so consider it a success🙂

Excellent way of looking at it - all teeth and bones intact is a win. It only went after I’d fitted and removed it once due to the wrong BB length, too, so considering myself lucky.

This dimple here probably created a stress point.

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Was fettling my partner’s bike when I realised that the rear wheel had some side to side play while in dropouts. Realised that there is play between the skewer and the wheel hub (I can push the skewer up and down when inserted, as shown by the not very obvious picture) - is this common or is the hub knackered?

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