Stuff you learn(t) the hard way by being your own mechanic

[Zebra]

On 3/25/2023 at 2:40 PM, mazambaan said:

…..a flimsy bit of ill fitting plastic holding a rat nest of randomly coiled wires and held on with allen screws usually seen in a cheap watch. One of these toy screws is…

…you have a WAY with words, I had a GOOD chuckle, could almost HEAR the frustration in your words! Re-read it twice, yes, a good chuckle. And informative, too!
Cheers

Chris

[MORNE]

Yes you will drop that grub screw and lose it, and no you don’t have a spare in your screws box…because who does……… 

[BaGearA]

3 minutes ago, MORNE said:

Yes you will drop that grub screw and lose it, and no you don’t have a spare in your screws box…because who does……… 

Grub screws are like 5c each

 

I have a moerse collection just bause of this reason and it cost me like 60 bucks , i keep them in one of those plastic trays with all the small compartments from plastilon

[Paul Ruinaard]

what are some brands of ebike chains or how do you recognize them.

 

[MrJacques]

12 minutes ago, Paul Ruinaard said:

what are some brands of ebike chains or how do you recognize them.

 

They will usually say that they're for e-bike, e.g. KMC X12E.

[ChrisF]

23 minutes ago, Paul Ruinaard said:

what are some brands of ebike chains or how do you recognize them.

 

 

KMC has a very nice ebike chain. I typically buy it at Evobikes

 

More often than not the Shimano ebike chain is the 116-link chain ....  then you get home to realise it is too short.

[MrJacques]

Done with oil based lubes, what a mess to clean a chain that's been oiled. (Road bike).

[dasilvarsa]

2 minutes ago, MrJacques said:

Done with oil based lubes, what a mess to clean a chain that's been oiled. (Road bike).

1/2 Wax 1/2 Mineral Oil is also cr@p

100% Wax Water Emulsion is the way to Go (Squirt or Smoove)

[MrJacques]

22 minutes ago, dasilvarsa said:

1/2 Wax 1/2 Mineral Oil is also cr@p

100% Wax Water Emulsion is the way to Go (Squirt or Smoove)

Smoove is on my short list, I'm keen to give it a try.

I'm also keen to give Wurth HHS a try, but it's a spray on wax lube, so I'd put it into a syringe to drip onto the chain.

Ona related note, it's a pity that we don't get Pedros products here anymore. Their degreaser is the best I've used, the oil dissolves so easily. Their other products (e.g. bike polish) and tools are very nice as well.

[ChrisF]

A few weeks back I had a nasty high speed tumble during an event outside Ashton.

 

Three consecutive LONG and very STEEP downhill sections, well actually just one massive long section with turns that created the impression of a 150m section at a time.

 

By the end of the second section the brakes on my bike started glazing/over heating ..... by the third section I was hanging on for dear life and hoping the trail would level out after the next turn ..... not to be.

 

Thankfully no broken bones, just a lot of roasties, and some very tender spots for a few weeks.  More importantly, just a torn bar grip, no other damage.

 

 

 

So, time to figure out why  the brakes overheated .... any technical issues other than simply the length and gradient ?

 

 

Checking the bike around the block all seemed fine.

 

30km ride of the local trails, deliberately including some short steep declines.  Sessioning a few sections to test long slow braking vs short fast braking .... still all seems fine.

 

The next weekend I repeated some of these tests, and ended it off with a decent of Odendaal ..... tar, long, steep ....  I deliberately picked up a lot of speed at the top of the hill, and then did some hard braking during the first half.  Fine ... fine ... uhmmm .... followed by a horrible grinding sound ....  Stopped, checked, all looks fine.  Ride, stop, fine ...  I repeat the fast steep test, and again it starts grinding towards the end of the hard braking.  

 

PS - Now I KNOW how this bike handles down Odendaal, and how the brakes react to hard braking from 70km/h down to stopping.

 

Okay, so something IS wrong.  But visually all seems good, normal trail riding the bike test fine.

 

 

Off to the LBS ..... one look, and he points to the "slight ridge" on the brake rotor.

 

Back at home, time to play with the micrometer ....

 

Shimano rotors are sold at about 1,8mm thickness, actually measured as 1,76mm with a micrometer.

 

 

Front brake disc looks very good .... but measure in at 1,41mm.   Shimano recommending a minimum of 1,5mm disc thickness.

 

 

Rear disc has worked hard and measures in at 1,06mm   Clearly that "little ridge" should be treated as a big red flag !!

 

 

 

New rotors fitted.  New brake pads fitted.   ..... need to do the Shimano bleed-cup thing to get some space between the new pads for the new thick rotors.  (will do that in day light)

 

 

GLAD I bought rotors a while back when they had stock.  No stock today .....

 

 

 

feedback from the more experienced riders and mechanics will be appreciated.  Is this type of overheating/glazing typical of rotors that are too thin ?  Any recommendations ?

[BaGearA]

9 minutes ago, ChrisF said:

A few weeks back I had a nasty high speed tumble during an event outside Ashton.

 

Three consecutive LONG and very STEEP downhill sections, well actually just one massive long section with turns that created the impression of a 150m section at a time.

 

By the end of the second section the brakes on my bike started glazing/over heating ..... by the third section I was hanging on for dear life and hoping the trail would level out after the next turn ..... not to be.

 

Thankfully no broken bones, just a lot of roasties, and some very tender spots for a few weeks.  More importantly, just a torn bar grip, no other damage.

 

 

 

So, time to figure out why  the brakes overheated .... any technical issues other than simply the length and gradient ?

 

 

Checking the bike around the block all seemed fine.

 

30km ride of the local trails, deliberately including some short steep declines.  Sessioning a few sections to test long slow braking vs short fast braking .... still all seems fine.

 

The next weekend I repeated some of these tests, and ended it off with a decent of Odendaal ..... tar, long, steep ....  I deliberately picked up a lot of speed at the top of the hill, and then did some hard braking during the first half.  Fine ... fine ... uhmmm .... followed by a horrible grinding sound ....  Stopped, checked, all looks fine.  Ride, stop, fine ...  I repeat the fast steep test, and again it starts grinding towards the end of the hard braking.  

 

PS - Now I KNOW how this bike handles down Odendaal, and how the brakes react to hard braking from 70km/h down to stopping.

 

Okay, so something IS wrong.  But visually all seems good, normal trail riding the bike test fine.

 

 

Off to the LBS ..... one look, and he points to the "slight ridge" on the brake rotor.

 

Back at home, time to play with the micrometer ....

 

Shimano rotors are sold at about 1,8mm thickness, actually measured as 1,76mm with a micrometer.

 

 

Front brake disc looks very good .... but measure in at 1,41mm.   Shimano recommending a minimum of 1,5mm disc thickness.

 

 

Rear disc has worked hard and measures in at 1,06mm   Clearly that "little ridge" should be treated as a big red flag !!

 

 

 

New rotors fitted.  New brake pads fitted.   ..... need to do the Shimano bleed-cup thing to get some space between the new pads for the new thick rotors.  (will do that in day light)

 

 

GLAD I bought rotors a while back when they had stock.  No stock today .....

 

 

 

feedback from the more experienced riders and mechanics will be appreciated.  Is this type of overheating/glazing typical of rotors that are too thin ?  Any recommendations ?

They were simply worn out 

 

I have seen brakes overheat and get contaminated but have never seen glazing with my own eyes.

 

I'm fairly light on rotors but only use metal pads so my rotors last about two years if I don't smash them

 

Like your pads they're consumables, but you might benefit from uping in size.

 

Ie move the fromt rotor to the rear and go 20mm larger infront , should significantly improve power and hopefully you then you use them slightly less and get better life.

 

 

There's also something to be said for a good rotor, I've always been on XT ice tech's but almost 6 months on sram Centreline's and really can't tell a difference in performance. But i would not expect the same from a 1R90 Solomon's special 

[ChrisF]

55 minutes ago, BaGearA said:

They were simply worn out 

 

I have seen brakes overheat and get contaminated but have never seen glazing with my own eyes.

 

I'm fairly light on rotors but only use metal pads so my rotors last about two years if I don't smash them

 

Like your pads they're consumables, but you might benefit from uping in size.

 

Ie move the fromt rotor to the rear and go 20mm larger infront , should significantly improve power and hopefully you then you use them slightly less and get better life.

 

 

There's also something to be said for a good rotor, I've always been on XT ice tech's but almost 6 months on sram Centreline's and really can't tell a difference in performance. But i would not expect the same from a 1R90 Solomon's special 

 

Shimano 203 rotors, front and rear.  4-pod XT brakes, with resin pads.

 

As you say, just normal wear and tear.

 

 

In the spirit of this thread : "What have we learnt" .....

1. A slight ridge on a brake rotor deserves a closer look !!

2. The brakes still work perfectly in all other conditions .... but overheating when the downhill carries on aint "fun" ....

 

 

Maybe a topic for another post .... resin vs metal pads ....

Edited April 15, 2023 by ChrisF

[love2fly]

1 hour ago, ChrisF said:

A few weeks back I had a nasty high speed tumble during an event outside Ashton.

 

Three consecutive LONG and very STEEP downhill sections, well actually just one massive long section with turns that created the impression of a 150m section at a time.

 

By the end of the second section the brakes on my bike started glazing/over heating ..... by the third section I was hanging on for dear life and hoping the trail would level out after the next turn ..... not to be.

 

Thankfully no broken bones, just a lot of roasties, and some very tender spots for a few weeks.  More importantly, just a torn bar grip, no other damage.

 

 

 

So, time to figure out why  the brakes overheated .... any technical issues other than simply the length and gradient ?

 

 

Checking the bike around the block all seemed fine.

 

30km ride of the local trails, deliberately including some short steep declines.  Sessioning a few sections to test long slow braking vs short fast braking .... still all seems fine.

 

The next weekend I repeated some of these tests, and ended it off with a decent of Odendaal ..... tar, long, steep ....  I deliberately picked up a lot of speed at the top of the hill, and then did some hard braking during the first half.  Fine ... fine ... uhmmm .... followed by a horrible grinding sound ....  Stopped, checked, all looks fine.  Ride, stop, fine ...  I repeat the fast steep test, and again it starts grinding towards the end of the hard braking.  

 

PS - Now I KNOW how this bike handles down Odendaal, and how the brakes react to hard braking from 70km/h down to stopping.

 

Okay, so something IS wrong.  But visually all seems good, normal trail riding the bike test fine.

 

 

Off to the LBS ..... one look, and he points to the "slight ridge" on the brake rotor.

 

Back at home, time to play with the micrometer ....

 

Shimano rotors are sold at about 1,8mm thickness, actually measured as 1,76mm with a micrometer.

 

 

Front brake disc looks very good .... but measure in at 1,41mm.   Shimano recommending a minimum of 1,5mm disc thickness.

 

 

Rear disc has worked hard and measures in at 1,06mm   Clearly that "little ridge" should be treated as a big red flag !!

 

 

 

New rotors fitted.  New brake pads fitted.   ..... need to do the Shimano bleed-cup thing to get some space between the new pads for the new thick rotors.  (will do that in day light)

 

 

GLAD I bought rotors a while back when they had stock.  No stock today .....

 

 

 

feedback from the more experienced riders and mechanics will be appreciated.  Is this type of overheating/glazing typical of rotors that are too thin ?  Any recommendations ?

I was once told by a guy at AutoZone that on a car a 1mm drop in thickness (so a 1mm lip) which as a % of a car disc isn't much, equates to a 100 degree increase in temp. I'm guessing the less metal you have the higher the temperature, which feeds into the fluid, plus the pistons are at max extension.

[droo]

On 4/15/2023 at 7:41 PM, ChrisF said:

 

Shimano 203 rotors, front and rear.  4-pod XT brakes, with resin pads.

 

As you say, just normal wear and tear.

 

 

In the spirit of this thread : "What have we learnt" .....

1. A slight ridge on a brake rotor deserves a closer look !!

2. The brakes still work perfectly in all other conditions .... but overheating when the downhill carries on aint "fun" ....

 

 

Maybe a topic for another post .... resin vs metal pads ....

The ridge wasn't your problem, the thickness was. Anything below spec, especially on an ebike, and it's time to replace.

If it's an IceTech rotor, then by the time you get down to about 1.2mm you're past the steel friction material and down to the alu core in places, which will make horrible noises.

[ChrisF]

1 hour ago, droo said:

The ridge wasn't your problem, the thickness was. Anything below spec, especially on an ebike, and it's time to replace.

If it's an IceTech rotor, then by the time you get down to about 1.2mm you're past the steel friction material and down to the alu core in places, which will make horrible noises.

 

Thanks @droo

 

 

I was trying to get the message across that "the ridge" might be the only visible clue .... until it is too late, and you are going full speed down a mine shaft ...   VERY gratefull I did not break bones in this crash ....  5 weeks later and still some roasties and every so often a numb feeling in my leg.

 

Can just SEE myself getting that micrometer out at the slightest sign of any ridge .... 

[Frosty]

Not so much a mistake, but a day of struggling with my new chain (on Friday). Struggled to break the chain at the 4th link (112 length). Turns out the pin has broken off on my Park Tool chain breaker. Thankfully I see there is a replacement tool pin.

Also struggled to click the new master link together. Had to use the tool, that I’ve had in the toolbox for years, but never used. It was super tight trying by hand.

Once on, I realised I put the chain on the wrong way. Unclick. Turn around. Reinstall.

Then realised it was upside down… OCT (tendencies, not disorder) says the Shimano logo must be right way up when on the top of the chain ring, like the crankset logo.

Anyway, sanity prevailed and a short while later I was done. New chain days are awesome.