Mechanics Quick Question Thread [Ask Questions Here]

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Mechanics Quick Question Thread [Ask Questions Here]
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flag adm750
Posted: May 18, 2021 at 13:06 Quote
Gents - Is it possible that when the suspension compresses, the forward part of the shock is contacting the mounting bracket...? Causing just a slight bend in the shaft that leads to failure...?

Am I thinking of this correctly...?

The rear part of shock travels downward (dotted red arrow) under suspension compression right ? Which rotates the shock effectively clockwise around the forward pivot, possibly allowing the head to impact the bracket (solid red arrow) or creat some other form of binding we can't see, thus putting bending stress on the shock shaft...?

photo
flag seraph
Posted: May 18, 2021 at 13:36 Quote
ScaryGuiTarS wrote:
Chain maintenance.

This is kind of trivial but I thought the best forum for posting this kind of question.

I'm having this give-n-go w/a guy on Quora about chain maintenance. It was because he's recommending NOT to clean your chain when you lube it. I'm like, what? I'm a scrub, degrease, clean again, repeat if necessary, THEN lube. I'm always trying to keep as much old grease, dirt, debris, sand, etc, out of my drivetrain parts as possible.

An I really way-off on this? I've just never heard of being advised to LEAVE all that crap on your parts!

I don't need to get into how much more efficient everything works when I do that, not to mention how much longer everything lasts as well, but I thought I'd question how many people here see this differently, OR what advice others here give about chain maintenance.

~JSV

If you're interested in the comments:
https://www.quora.com/What-are-some-good-maintenance-tips-for-keeping-my-fancy-new-road-bicycle-running-like-new/answer/Drew-Eckhardt?comment_id=200261137&comment_type=2

I worked with a guy who swore up and down that you weren't supposed to clean your chain, that there were natural cleaning agents in chain lube. But then this was also a mechanic who hadn't ridden a bike for more than 15 minutes in about 10 years. I call them "theoretical cyclists" or "armchair mechanics".

That said, I really like fully degreasing my chain.
flag tannerzinck
O+
Posted: May 18, 2021 at 14:25 Quote
adm750 wrote:
Gents - Is it possible that when the suspension compresses, the forward part of the shock is contacting the mounting bracket...? Causing just a slight bend in the shaft that leads to failure...?

Am I thinking of this correctly...?

The rear part of shock travels downward (dotted red arrow) under suspension compression right ? Which rotates the shock effectively clockwise around the forward pivot, possibly allowing the head to impact the bracket (solid red arrow) or creat some other form of binding we can't see, thus putting bending stress on the shock shaft...?

photo

Looks plausible
flag ScaryGuiTarS
Posted: May 18, 2021 at 16:13 Quote
R-M-R wrote:
ScaryGuiTarS,

freestyIAM is correct, with the caveat this works best with a fairly clean lube. If your chain is a thick, black mess when you re-lube, the cleaning burden is more than can be accomplished with using lube as both solvent and lubricant. It's also a cue to change your lube and/or your method.

I use Rock n Roll Absolute Dry (red) with the method described by freestylAM (every ride, with only one cycle; no repetition required) and my chain is completely clean. It's indistinguishable from one that's been run through a solvent bath and ultrasonic cleaner. My drivetrains last at least two to three times longer than typical.
I'd say I'm pretty much in agreement with most or all of this myself too. I never advocated to completely sterilize a chain regularly, but I can't see people thinking that leaving ALL the gunk and deposits on there is actually a good thing--for your chain, components, anything.

I'd say that only once in a while, if it's really getting hard to wipe down, or I can actually HEAR or FEEL a gritty thing going on in there, then I will completely degrease and properly re-lube the chain. It's hard to convey the language here I guess, but many of you know that there are methods of properly lubing the pins and rollers and checking to see if your chain is safely lubed to ride with. My cassettes are lasting long, chains lasting, gears change with no issues and hardly ever have to adjust or re-index , but in years past with the bikes where I've left ON a lot of that dirt and grime and just tried to "lube over" it, nothing worked that well so often, and parts were being replaced and readjust much more often.

Well it's another interesting bike maintenance thing that's great to discuss out of the curiosity for how people basically do things a little different, but generally have the same ideas or vision. I just would find it hard to believe that ANYONE knowledgeable on this topic would advocate leaving in all that grime on their important and expensive parts, as that gentleman had recommended.

With that said... I now have plans for a Evil ~sP00Ky~Eek ~nigHT~Eek ~rIdE~Evil in the WOODS... hope we don't get EATEN...


...by the WITCH!

~JSV
flag R-M-R
Posted: May 18, 2021 at 18:43 Quote
adm750, tannerzinck;

No, there is essentially zero rotation at the forward shock mount on Canfields. The shock body is not contacting the frame.


ScaryGuiTarS, chain cleaning people;

Below is a photo of my chain after a very short ride. Wipe, lube, wipe - nothing more. Rock n Roll Absolute Dry, which I highly recommend.

photo
flag cyberoptixs
Posted: May 18, 2021 at 20:16 Quote
I'm thinking of doing a mullet on my nephew's bike it's currently a 26er with 170mm front and rear ... Was thinking of doing 170mm with a 27.5 up front ... How much would it mess the Geo up? Bike has a 66 degree HT at the moment ... Only think this cuz his fork is almost toast and 26 inch forks are hard to find and way over priced
flag R-M-R
Posted: May 18, 2021 at 20:34 Quote
cyberoptixs,

Assuming the change in axle-to-crown of the new fork is directly related to wheel size (as is usually the case, or very close) it will raise the front end 1", since 27.5" is 0.98" larger than 26" (not the claimed 1.5" difference). This will make the head-tube angle about 1.1° slacker and the BB will be about 8 mm higher.

You could approximately halve the change by using a 160 mm fork. Not a big deal either way, so go ahead with whatever fork you can find on sale!
flag naptime
Posted: May 18, 2021 at 20:57 Quote
R-M-R wrote:
cyberoptixs,

Assuming the change in axle-to-crown of the new fork is directly related to wheel size (as is usually the case, or very close) it will raise the front end 1", since 27.5" is 0.98" larger than 26" (not the claimed 1.5" difference). This will make the head-tube angle about 1.1° slacker and the BB will be about 8 mm higher.

You could approximately halve the change by using a 160 mm fork. Not a big deal either way, so go ahead with whatever fork you can find on sale!

Recently went from 26 to 27 on my trail bike and can confirm precisely 8mm measured from tyre to fork brace. 26" magic Mary to 27" aggressor.
flag melanthius
O+
Posted: May 18, 2021 at 22:56 Quote
You're fine running a 27.5 fork. As the others said the geo change won't be that big of a deal. You don't even need to run a 27.5 wheel. In fact keeping the 26 wheel will keep the geo closer to the original. Probably will need a boost conversion kit for the wheel but it will run fine.
flag Joebohobo
Posted: May 19, 2021 at 4:48 Quote
R-M-R wrote:
cyberoptixs,

Assuming the change in axle-to-crown of the new fork is directly related to wheel size (as is usually the case, or very close) it will raise the front end 1", since 27.5" is 0.98" larger than 26" (not the claimed 1.5" difference). This will make the head-tube angle about 1.1° slacker and the BB will be about 8 mm higher.

You could approximately halve the change by using a 160 mm fork. Not a big deal either way, so go ahead with whatever fork you can find on sale!

Wouldn't it only raise the front end by half an inch? If total wheel is 1" bigger, and the axle is in the centre, then surely the axle is only half an inch higher than compared to a 26" wheel
flag Joebohobo
Posted: May 19, 2021 at 4:51 Quote
adm750 wrote:
Gents - Is it possible that when the suspension compresses, the forward part of the shock is contacting the mounting bracket...? Causing just a slight bend in the shaft that leads to failure...?

Am I thinking of this correctly...?

The rear part of shock travels downward (dotted red arrow) under suspension compression right ? Which rotates the shock effectively clockwise around the forward pivot, possibly allowing the head to impact the bracket (solid red arrow) or creat some other form of binding we can't see, thus putting bending stress on the shock shaft...?

photo

Unwind the spring (not sure the specific name of the part on the shock that threads and holds the spring in), and then compress the bike without the spring to see what happens
flag R-M-R
Posted: May 19, 2021 at 6:38 Quote
Joebohobo wrote:
Wouldn't it only raise the front end by half an inch? If total wheel is 1" bigger, and the axle is in the centre, then surely the axle is only half an inch higher than compared to a 26" wheel

Half an inch below the axle, plus the fork is half an inch longer to accommodate the larger wheel. Total: 1". The fork isn't vertical, so we're rounding a little here, but it's close enough to 1".
flag cyberoptixs
Posted: May 19, 2021 at 6:41 Quote
Cool thanks for the info RMR
flag leftypumpkin
O+
Posted: May 19, 2021 at 6:53 Quote
All this talk about chains - can I run a 10 speed chain on a 9 speed drivetrain? Long story - I bought two chains to get the extra 6 links I needed for my fatbike last year and I might just be able to squeak out a new chain for my summer bike from what's left.

Thanks.
flag adm750
Posted: May 19, 2021 at 6:57 Quote
Joebohobo wrote:
adm750 wrote:
Gents - Is it possible that when the suspension compresses, the forward part of the shock is contacting the mounting bracket...? Causing just a slight bend in the shaft that leads to failure...?.....

Unwind the spring (not sure the specific name of the part on the shock that threads and holds the spring in), and then compress the bike without the spring to see what happens

joebohobo....if you were replying to me, I thank you. But....I'm an idiot. I should have put my post as a "reply" to the discussion that started here:

https://www.pinkbike.com/forum/listcomments/?threadid=139436&pagenum=3431

I have an old bomb of a bike...not a cool one like the one they are discussing Wink

 


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