Is putting a slightly bigger shock on a frame than the one it's designed for that bad?

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Rear Shocks
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Suspension
westeegarden
I posted this on pinkbike, but I thought I would ask vital users too. to be specific, my bike is designed around and operating a 190x51mm shock, and I want to upgrade that shock. There are so many nice shocks out there (e.g. Fox float X2) that aren't made in 190x51, but are made in 200x55mm for example. Would putting on a shock with an eye-to-eye that's 10mm too long be that bad for geometry and suspension performance, or would I be ok? Or, going the opposite direction, if I ran a trunnion 185x50mm shock that's 5mm too short, would I bottom out harshly due to the lower starting point?
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bturman
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bturman 3/19/2020 9:45am
3/19/2020 9:45am
Changing eye-to-eye is a bad idea. Changing stroke by a few mm is possible on some bikes and will give you extra travel, but you must verify bottom-out clearance. Keep in mind that frames flex and bottom-out bumper squish during big impacts.

What bike are you on?

More on this topic: https://www.vitalmtb.com/forums/The-Hub,2/Game-Show-Will-It-Clear,10041
Scrub
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Scrub 3/19/2020 10:06am
3/19/2020 10:06am
Offset eyelet bushings are an option too if you are insistent on a different shock length. But i'd never run a shock that was too long for the frame..I did run shorter shocks with benefits of lower BB height and slack HT angle, but this was back in a time when bike geometry was whack. lol. Verify your clearances before investing!
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westeegarden 3/19/2020 10:19am
3/19/2020 10:19am
bturman wrote:
Changing eye-to-eye is a bad idea. Changing stroke by a few mm is possible on some bikes and will give you extra travel, but you must...
Changing eye-to-eye is a bad idea. Changing stroke by a few mm is possible on some bikes and will give you extra travel, but you must verify bottom-out clearance. Keep in mind that frames flex and bottom-out bumper squish during big impacts.

What bike are you on?

More on this topic: https://www.vitalmtb.com/forums/The-Hub,2/Game-Show-Will-It-Clear,10041
Marin Hawk Hill. I was just thinking of going and seeing how much clearance I had. thanks for the advice
westeegarden 3/19/2020 11:46am
3/19/2020 11:46am
Scrub wrote:
Offset eyelet bushings are an option too if you are insistent on a different shock length. But i'd never run a shock that was too long...
Offset eyelet bushings are an option too if you are insistent on a different shock length. But i'd never run a shock that was too long for the frame..I did run shorter shocks with benefits of lower BB height and slack HT angle, but this was back in a time when bike geometry was whack. lol. Verify your clearances before investing!
I've looked at the offset bushings, can you use them to increase eye-to-eye length? I'd imagine so but their main selling point is decreasing eye-to-eye and slackening geometry and it says nothing about possibly increasing.
Big Bird
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Big Bird 3/19/2020 12:15pm
3/19/2020 12:15pm
Adding eye to eye length would steepen your HA and raise your BB. The offset bushings would counter act that effect. But as Butters said, you have to know about that clearance.
pohsoonteng
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pohsoonteng 3/19/2020 1:24pm
3/19/2020 1:24pm
My Fluid actualy has 2.5mm more stroke with the same eye to eye than stock bring the rear travel to 127mm as opposed to the stock 120mm. Works pretty well. Think as long as you have clearance you're okay with a little extra. Not too sure about running a longer eye to eye though you could probably mitigate geo changes with offset bushings? Once again, just check for clearance. Also seeing what the leverage curve looks like would also be a good thing to check to see what it effectively does to your bike through it's stroke

https://www.youtube.com/watch?v=gT6g_519yoo
metadave
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metadave 3/19/2020 7:06pm
3/19/2020 7:06pm
Yea make sure you test one first. I'm sure a friend or a local shop need will have a shock you can install and do a bottom out test to make sure there's no frame contact. A friend did it with an older intense spider going from a 200x51 to a 200x57 and before he got offset bushings there was light frame contact with the rear triangle. If you don't test it, don't do it
westeegarden 3/20/2020 10:22am
3/20/2020 10:22am
Update: after research, I found that with offset bushings and a 200x50-57mm shock, I'd be all set for clearance, but still 6mm too long on the eye to eye. That seems like so little to me, but based on offset bushing's website, it sounds like it would raise the bb 15mm and steepen the head tube by 1.5°. Would it really? With a slightly longer travel fork that I plan on putting on, the HTA would stay about the same, but the bb would rise from 337mm to a little over 360mm. Not something I'm super keen on, but this is purely based on calculations scrapped together from different websites. Do you think I could remedy only 6mm with sag? Personal experience is always welcome.
Scrub
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Scrub 3/20/2020 12:05pm
3/20/2020 12:05pm
Let's be clear westeegarden, and answer these questions. What is the specific year and model of your bike? Have you actually measured the current shock correctly?

I ask this because I did some homework and the 2019-2020 Marin Hawk Hill 1 comes with a 210x50mm shock according to the Marin website.
westeegarden 3/20/2020 1:00pm
3/20/2020 1:00pm Edited Date/Time 3/20/2020 1:58pm
Scrub wrote:
Let's be clear westeegarden, and answer these questions. What is the specific year and model of your bike? Have you actually measured the current shock correctly...
Let's be clear westeegarden, and answer these questions. What is the specific year and model of your bike? Have you actually measured the current shock correctly?

I ask this because I did some homework and the 2019-2020 Marin Hawk Hill 1 comes with a 210x50mm shock according to the Marin website.
Its 2018. The marin website says 190x51mm. I guess I just missed having a more common shock size.

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