the 'there's no such thing as a stupid question' bike maintenance thread

CramCycle

CormacH94 wrote: »

Question on gearing/swapping gearing - If I have a 53/39 crank with an 11/27 cassette is it possible to switch to a 50/34 and an 11 -28 with little hassle?

My understanding is all I need are new chainrings, cassette and new chain? Will the front derailleur accept a low gearing? Or what size cages on FD and RD are needed for this combination?

magicbastarder wrote: »

I don't think there are any RDs which can take 27 tooth but not 28; and FDs are not compact or semi compact specific. You might even be able to reuse the chain if it's got little wear, but that would be the cheapest component you'd be replacing anyway.

All you technically need are the new chainrings. The chain will be slightly too long but I have gotten away with it, it's not by much. Possibly have to move the FD down a smidgen, but again, I got away with doing nothing on my commuter.

07Lapierre

CormacH94 wrote: »

Question on gearing/swapping gearing - If I have a 53/39 crank with an 11/27 cassette is it possible to switch to a 50/34 and an 11 -28 with little hassle?

My understanding is all I need are new chainrings, cassette and new chain? Will the front derailleur accept a low gearing? Or what size cages on FD and RD are needed for this combination?

A 53/39 crankset will have BCD of 130mm, whereas a compact crankset has a BCD of 110, so you need to confirm the BCD before purchasing chainrings. AFAIK, you will need a new chainset if you want a 50/34 chainrings

Question for others when you replace cables do you replace the outers too? I always have and never really thought about it until tonight as I've run out and won't have enough to do the job. So I'll have to reuse some of the ones already on the bike.

I should at least clean them out with some degreaser or something and leave to dry right? or should I be a lazy bastard and just feed the new cables through?

I think I know the answer :pac:

swarlb

07Lapierre wrote: »

A 53/39 crankset will have BCD of 130mm, whereas a compact crankset has a BCD of 110, so you need to confirm the BCD before purchasing chainrings. AFAIK, you will need a new chainset if you want a 50/34 chainrings

Do you mean PCD ? Pitch Circle Diameter What does BCD mean ?

CormacH94

Weepsie wrote: »

Not necessarily. The 4 armed newer shimano ones are all just 110 bcd. I've swapped 53/39 for compact on a 5800 chainset.

That said, it's often cheaper to just get a new crankset

For reference it's the older 5 arm Shimano - does this affect the BCD?

irishrover99

brownian wrote: »

An option is to fit an inline barrel adjuster to the FD cable. This is, I think, a nice longer-term solution, because it's in the nature of derailleurs to need tweaking. The adjuster costs a fiver or so, and fitting is easy enough (fiddlier if internal cable routing, of course).

I’ll look into this, thanks, but as an update, dropped the bike to joe Daly’s this morning and they could not find any issues with the set up of the front derailleur. They said maybe to try the new r7000 derailleur to see if that helps. Not sure what to do now as I’m lost to see how this issues could be due to it been the 5800 derailleur.

CormacH94

Looks like the older 5 arm Shimano crank has different BCD (I'm guessing this is bolt circle diameter for crank bolts?) it's 130 for the double crank and 110 for the compact

Easier to just buy a whole compact crankset?

Edit: Looking for 105 compact cranksets (5750) with 170mm arms - seems to be like hens teeth

07Lapierre

swarlb wrote: »

Do you mean PCD ? Pitch Circle Diameter What does BCD mean ?

Yep...Bolt Circle Diameter.

grogi

swarlb wrote: »

Do you mean PCD ? Pitch Circle Diameter What does BCD mean ?

Bolt Circle Diameter. https://thecyclemechanic.co.uk/bolt-circle-diameter

swarlb

grogi wrote: »

Bolt Circle Diameter. https://thecyclemechanic.co.uk/bolt-circle-diameter

Same thing, different terminology......
I suppose coming from a motoring background I'm used to PCD

https://en.wikipedia.org/wiki/Pitch_Circle_Diameter

JMcL

Deleted User wrote: »

Question for others when you replace cables do you replace the outers too? I always have and never really thought about it until tonight as I've run out and won't have enough to do the job. So I'll have to reuse some of the ones already on the bike.

I should at least clean them out with some degreaser or something and leave to dry right? or should I be a lazy bastard and just feed the new cables through?

I think I know the answer :pac:

You should, but in practice you should be grand unless you've been picking up lots of crud over the winter that'll have worked it's way in. The last couple of changes I've done, I haven't bothered with the outers as a) I was in a rush and b) wasn't in the humour for unwrapping/rewrapping the bar tape. I sprayed them with a bit of PTFE lube and they've been grand. Gear cables are a bit more pernicity than brakes I'd imagine, though that's based on no sound knowledge other than mere supposition!

CormacH94

Anyone explain in laymans terms what I'd be able to do to swap out a 105 5700 53/39 170.2mm crank for a 50/34 170mm crank?

Head is melted trying to figure out compatibility between generations

Can I use a newer 105 crankset (R7000) on a 10 speed 105 system with no issues?

Or can I use Tiagra 4700 cranks?

grogi

CormacH94 wrote: »

Anyone explain in laymans terms what I'd be able to do to swap out a 105 5700 53/39 170.2mm crank for a 50/34 170mm crank?

Head is melted trying to figure out compatibility between generations

Can I use a newer 105 crankset (R7000) on a 10 speed 105 system with no issues?

Or can I use Tiagra 4700 cranks?

I ride 11 speed Ultegra crankset with otherwise 10 speed Tiagra. No issues. The distance between chainrings is the same in 10 and 11speed front chainsets.

crosstownk

CormacH94 wrote: »

Can I use a newer 105 crankset (R7000) on a 10 speed 105 system with no issues?

Or can I use Tiagra 4700 cranks?

I’d say both will work fine. Personally, I’d go for the R7000 simply just to future proof.

CormacH94

Will I run into any potential problems running a 50/34 with an 11/28 on a short cage rear derailleur?

magicbastarder

chainset is immaterial, but more short cage RDs are fine with 28 teeth. do you have a specific model you intend using?

Type 17

CormacH94 wrote: »

Will I run into any potential problems running a 50/34 with an 11/28 on a short cage rear derailleur?

The differences* are 33, which is the official limit from the Shimano specs (which make/model is yours?), but if it is a Shimano, their capacity specs are quite conservative anyway, so definitely no problem.

*Derailleur capacity = difference between 50 & 34 (16) + difference between 11 & 28 (17), so 33 in your case.

CormacH94

It'd be an R7000 50/34 - everything else is 105 5700

tnegun

Replaced the BB on the bike today and the improvement is immediately noticeable, feels more solid and better shifting front and back. There was a lot of play in the old one and it had fallen apart when I removed the cranks for cleaning a couple of weeks ago so needed to be done.

The replacement is a little stiff though I took it for a 30k spin to see would it loosen up but its the same after that. Is there a run in period with them? I loosened off the cranks to see had I over tightened but it didn't make any difference. It's not awful but definitely not spinning freely.Its an FSA BB4000 a direct swop for what was on the bike.

cletus

When I was re-installing the bottom bracket, I noticed that the axle had a longer taper on o e wide than the other. Having not noticed it when removing, I figured the longer side was to accommodate the triple chain ring on the drive side, and installed it so.

However, looking at it this evening, the chain line is too far to the outside of the chain stay, in fact it's falling in line with the drop out, basically.

Question is, am I ok to just take it out and swap it, leaving the longer side on the non drive side.



And yes, I am aware that the lock ring for the bottom bracket is not flat, it was like that when I got here...

Tony04

Each side of the bottom bracket uses different sided threads so AFAIK left hand threads arent compatible with right hand threads and vice versa.

Is the crank 1x or 3x if its 3x you can change which chainring you use to get the chain line right that's why if doing a 1x conversion it's best to keep your old crank or buy a new bottom bracket with a smaller longer diameter

Tony04

Seeing the picture you could move the chainring to the middle to improve the chain line

cletus

Tony04 wrote: »

Each side of the bottom bracket uses different sided threads so AFAIK left hand threads arent compatible with right hand threads and vice versa.

Is the crank 1x or 3x if its 3x you can change which chainring you use to get the chain line right that's why if doing a 1x conversion it's best to keep your old crank or buy a new bottom bracket with a smaller longer diameter

They're right hand thread on both sides.

8valve

cletus wrote: »

They're right hand thread on both sides.

Italian thread, so?

Tony04

cletus wrote: »

They're right hand thread on both sides.

Well if so you can swap as you like.

cletus

To clarify, it's just the axle of the bottom bracket I want to swap around. I'll leave the threaded cups in their respective positions.

The threads I was referring to are on the end of the taper, to hold on the cranks

Type 17

On many cup-and-cone BBs, the axle is longer on the non-drive side (not sure why, but maybe because older LH cranks are relatively straight, whereas newer styles have more lateral curve).

When removing older axles, I’ve found that on ones that have any writing on them (make, length, etc), the writing is the right way up when viewed from the saddle.

ec18

Do you need to bleed hydraulic discs after switching the hoses between the levers ?

Type 17

ec18 wrote: »

Do you need to bleed hydraulic discs after switching the hoses between the levers ?

If you’re lucky, then no, but if any air was admitted to the circuit (long lever travel, sponginess), then a quick burp (not a full bleed/fuid exchange with a syringe at the calliper) is in order - assuming the fluid is good (not old or contaminated), you can put a cup on the lever with some fluid in it, Angle the bike so air bubbles can flow up the circuit to the cup, and then work the lever/tap the pipework/lever with a screwdriver handle to encourage the bubbles to break free and rise up the circuit into the cup.
Keep tapping/working the lever for several minutes until the bubbles stop and the lever feels firm again.

cletus

Weepsie wrote: »

I have the cutting guide tool, hack saw and a file. It's not the cutting so much as the cutting it too much.

They're both touring frames, so want them fairly relaxed.

I cheapest out on the star nut tool too but will give that a go.

How did tyoyu get on with this, Weepsie