retrobiker273891
Retro Guru
I have bought https://www.retrobike.co.uk/threads/18”-gt-bravado.484294/
Everything is nice overall but requires a bit of maintenance for usage and a few issues are with parts I am not familiar with dealing with.
Firstly, there is some sort of damage to the cap/cover of the headset where the stem meets the headtube. The part which covers the ball bearings is not covering it properly and so the ball bearings are exposed in one section to the elements.
Can I replace just the plastic cap to cover the ball bearings again or will I have to get a whole new headset?
I will note that the headset seems perfectly functional otherwise so would like to be able to just replace that little cap if I can.
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Next thing, the crank when riding. I don't know if this is an intended 'feature' or requires some rejigging but I notice when I was pedaling sometimes the crank would not 'take' and take maybe a quarter to a half pedal before the crank would move the drivetrain again. What I mean is it was like freewheeling but in the opposite direction, for a couple of seconds, until it worked as expected again. So no forward momentum until it stopped doing whatever it was doing.
What is that?
Someone has replied on another forum that it means the hub is 'shagged' but they are really discouraging of any retro bike stuff and don't know if that is just their usual prejudice. Can it be fixed myself with some tlc?
I noticed it seemed related to my speed. I haven't ridden enough yet to get a clear idea of the pattern but it seemed that the faster I was going the larger the 'reverse freewheel' effect was and the slower then the less to almost indistinguishable it was.
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Another thing, the brakes.
As per the description it says parallel push V-brakes but, having experience maintaining them in the past, they do something I have not experienced before.
I had to tune the brakes but how things are is that the brake blocks are almost touching the rims already and yet the brake levers are almost fully depressed to get them to brake. This means I am unsure how to tune them more because pulling the wire further out will not help and since they are so close, and even rubbing a teensy bit still, I am unable to make the wire more taught.
In my past experience with brakes when there is little clearance at the brake blocks then there would be barely any lever tension on the brake levers and they would be taught. So it seems there is excess slack somewhere along the line for both front and back so not sure how to diagnose that as it isn't something I have experienced before. So advice on that please.
EDIT: Doing some more reading are my issues likely related to the 'parallel push' function?
Just found an article from sheldon brown which details some of their unique issues with these types and some possible remedies. I know the front one is squeaking a lot currently which they note in the post as a sign of them requiring some attention.
Looks like a case of stripping them down and figuring out what makes them tick.
Everything is nice overall but requires a bit of maintenance for usage and a few issues are with parts I am not familiar with dealing with.
Firstly, there is some sort of damage to the cap/cover of the headset where the stem meets the headtube. The part which covers the ball bearings is not covering it properly and so the ball bearings are exposed in one section to the elements.
Can I replace just the plastic cap to cover the ball bearings again or will I have to get a whole new headset?
I will note that the headset seems perfectly functional otherwise so would like to be able to just replace that little cap if I can.
---
Next thing, the crank when riding. I don't know if this is an intended 'feature' or requires some rejigging but I notice when I was pedaling sometimes the crank would not 'take' and take maybe a quarter to a half pedal before the crank would move the drivetrain again. What I mean is it was like freewheeling but in the opposite direction, for a couple of seconds, until it worked as expected again. So no forward momentum until it stopped doing whatever it was doing.
What is that?
Someone has replied on another forum that it means the hub is 'shagged' but they are really discouraging of any retro bike stuff and don't know if that is just their usual prejudice. Can it be fixed myself with some tlc?
I noticed it seemed related to my speed. I haven't ridden enough yet to get a clear idea of the pattern but it seemed that the faster I was going the larger the 'reverse freewheel' effect was and the slower then the less to almost indistinguishable it was.
---
Another thing, the brakes.
As per the description it says parallel push V-brakes but, having experience maintaining them in the past, they do something I have not experienced before.
I had to tune the brakes but how things are is that the brake blocks are almost touching the rims already and yet the brake levers are almost fully depressed to get them to brake. This means I am unsure how to tune them more because pulling the wire further out will not help and since they are so close, and even rubbing a teensy bit still, I am unable to make the wire more taught.
In my past experience with brakes when there is little clearance at the brake blocks then there would be barely any lever tension on the brake levers and they would be taught. So it seems there is excess slack somewhere along the line for both front and back so not sure how to diagnose that as it isn't something I have experienced before. So advice on that please.
EDIT: Doing some more reading are my issues likely related to the 'parallel push' function?
Just found an article from sheldon brown which details some of their unique issues with these types and some possible remedies. I know the front one is squeaking a lot currently which they note in the post as a sign of them requiring some attention.
Parallel-Push Linkage
v-type brake
Older Shimano's XTR and XT V-Brakes feature a special parallelogram linkage. This serves two purposes:
It causes the brake shoes to remain at the same angle to the rim throughout the stroke, and throughout the service life of the pad.
It causes the direction of motion of the brake shoes to be close to horizontal, rather than the usual slanted arc centered on the pivot boss. This is a major advantage for those who use very fat tires on narrow rims, because it prevents the shoe from rising up and damaging the sidewall of the tire on release, and also prevents having the brake shoes dive under the rim as they wear down.
Unfortunately, the extra pivots considerably complicate the mechanism, and this has caused maintenance problems and excessive squeal in practice.
Reader Paul Rintoule has sent in some advice on maintenance of parallel-push brakes:
Shimano parallel-push V-brake tune-up kits have all but dried up so I fixed my squealing XT parallel-push V-brakes by adding disc brake rotor washers to tighten up the parallel-push pivot cage. This works the same as the tune-up kit did.
Firstly, buy some disk brake rotor spacer/washers from a bike shop and super glue from the local supermarket, hardware store etc..
Remove the brake arms from the bike using a 5mm Allen key.
On your workbench, remove the brake pads.
Using a utility knife, peel off the silver stickers from the ends of the parallel-push cage pivot.
Take a photo of a parallel-push cage to remember the order of existing spacer and spring.
Remove the 2mm Allen set screw from each brake arm. You now can push out the parallel-push cage pivot.
Give the parts a wipe clean.
Now reassemble the brake arms and parallel-push cages including adding one or more rotor spacers between the brake arm and the parallel-push pivot cage to take up most of the slack. You want each pivot cage still to turn freely on its pivot without binding.
Replace the 2mm Allen set screw in each brake arm using blue threadlock compound.
Degrease the silver main pivot stickers and the ends of the main pivot using solvent and a cotton swab (Q-Tip).
Clean the brake pads with using solvent and sandpaper and then reattach.
Clean the wheel rims using solvent and sandpaper/fine steel wool.
Reattach the silver main pivot stickers using a small amount of super glue around their perimeter. When glue has set (10 or 20 seconds) reattach the brake arms to your bike, remembering to use blue threadlock compound on the main pivot bolts.
You have now removed the slack that causes severe squealing.
Looks like a case of stripping them down and figuring out what makes them tick.
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