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'18 Transition Sentinel
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Discussion Starter · #1 · (Edited)
I just picked up a Truvative Shiftguide (309g) to be mounted with an E-Type BB for my 4-bar full-sus (without ISCG tabs).

https://www.sram.com/en/truvativ/guidesandpedals/shiftguide/team.php
https://www.sram.com/_media/techdocs/2005_cg-03-boxguide-e-r6.pdf

The instruction says to position the lower-roller to point at 7~8 o'clock. The thing is, with my 22T/32T/bash combo, my 32T/max Truvative Rockguard bash is pretty small. So, if I aim it at 7 o'clock, the lower roller sticks out lower than the bottom of bash, which I'm afraid that I'm going to eventually hit the roller on something (rather than the bash hitting the object). On the other hand, if I point it at 8 o'clock, the roller gets very close to the chainstay. Is that OK? Should I just really get it so close that the chain (sitting above the lower roller) is just about to touch the chainstay? I wonder that'll be really loud/annoying when blasting down bumpy trails?

Also, the instruction says to set up the lower roller to contact the bash. Does that mean that the roller will be always spinning together with the bash at the speed of crank turning while pedaling (rather than spinning by the chain friction)?

Thanks for your helpful feedback (and/or pic's) in advance,
- PiroChu

 

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Old No. 7
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PiroChu said:
I just picked up a Truvative Shiftguide to be mounted with an E-Type BB for my 4-bar full-sus (without ISCG tabs).

http://www.sram.com/en/truvativ/guidesandpedals/shiftguide/team.php
http://www.sram.com/_media/techdocs/2005_cg-03-boxguide-e-r6.pdf

The instruction says to position the lower-roller to point at 7~8 o'clock. The thing is, with my 22T/32T/bash combo, my 32T/max Truvative Rockguard bash is pretty small. So, if I aim it at 7 o'clock, the lower roller sticks out lower than the bottom of bash, which I'm afraid that I'm going to eventually hit the roller on something (rather than the bash hitting the object). On the other hand, if I point it at 8 o'clock, the roller gets very close to the chainstay. Is that OK? Should I just really get it so close that the chain (sitting above the lower roller) is just about to touch the chainstay? I wonder that'll be really loud/annoying when blasting down bumpy trails?

Also, the instruction says to set up the lower roller to contact the bash. Does that mean that the roller will be always spinning together with the bash at the speed of crank turning while pedaling (rather than spinning by the chain friction)?

Thanks for your helpful feedback (and/or pic's) in advance,
- PiroChu
As long as the roller isn't touching the chainstay when you sus. is completly extended (bike off the ground incase it sags under it's own weight) you should be fine. And you can put the roller on the bash so it moves with it, or you can move it a tiny tiny bit to avoid it, doesn't really matter, as long as there isn't a big enough gap to lose your chain. I think I have a few milimeters between my bottom roller and bash.
 

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It should be more like 8-9 o' clock for the roller.

The top should be at about 12 o' clock, but if I'm not mistaken that guide has independent top and bottom pieces.

Don't let the roller touch the bash, there should be a gap of about 5mm there.
 

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'18 Transition Sentinel
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1,015 Posts
Discussion Starter · #5 · (Edited)
noise & mis-alignment ?

fred.r & Ojai Bicyclist:

Thanks for your helpful feedback.

I got the lower roller & upper block mounted, no prob (very close but not touching bash = silent). Then, I put all back together, and - while hand-pedaling on the bike stand - it's very noisy (more so than normally expected?) when in 32T/front. It's totally quiet when in 22T/front.

Looking closely, as in the diagram below, I noticed that the 32T is almost directly above where the step-down on the roller is (blue), yet the chain gets kind yanked to the side (red) in actuality. But, the chain almost seems to want to ride right on the step-down/step-up ridge of the roller, while pedaling; hence the super-loud noise. (Accordingly, when in 22T (green), the chain is almost on the roller's edge, closer to the plate side.) So, it almost seems as if I need to get the roller shifted closer towards non-drive side so that the the stepped-down plateau of the roller would line up directly underneath the 32T ring. FYI, I'm using a 68mm x 113mm BB (E-Type for mounting Shiftguide) for 47.5mm chain-line, per frame spec.

Looking at the instruction, there's no "5mm spacer" for Shiftguide roller (only for Boxguide) that I can take out to get the roller closer towards non-drive side. I suppose I could take out the thin washer (1mm~2mm?) between the roller & the plate to back the roller closer towards non-drive side for slightly better chain-vs-roller alignment. Not sure it's a good idea to skip the washer, though.

Any other ideas?
- PiroChu
 

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Old No. 7
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Noise is somewhat normal for guides. How much noise is hard to describe, but a little to some is normal. If you think removing a spacer or washer will help with chain to roller alignment go for it, as long as your roller can freely move you should be fine. You can really try what ever and use what works best, it's not a crazy fragile adjustment, just find what works best and use it. I've grinded rollers, melted them ect... to get them to hold my chain better, do what works.
 

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Is your BB spindle too long?

Also, the roller should be floating. Does it still not have enough movement to properly line up?

I've only dealt with the Boxguide, so I'm not too familiar with that model. I would say take out that washer and try everything you can to make it work better. You should see some of the jurry-rigging I do to my guides. Filing, sawing, sanding, using a bunch of crap laying around as washers, etc.
 

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'18 Transition Sentinel
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Discussion Starter · #8 · (Edited)
grinding, filing, sawing, sanding ?

fred.r & Ojai Bicyclist:

It's good to know that this thing isn't a precision rocket science but rather a caveman science doing whatever it takes. :D

On that note, what are some good ways to cut out urethane roller neatly? I feel that I need to cut out the stepped-up area on roller a bit (yellow in diagram) in order to line up the chain better when on 32T/middlering. What did you use & how to file, sand, cut, chop, grind it down, etc? (Do you have any pic's?)

Or, alternatively, I wonder if I can use a roller from e13 DRS or MRP LRP - just something that has narrower stepped-up & wider stepped-down plateau...?


Thanks again,
- PiroChu
 

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'18 Transition Sentinel
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Discussion Starter · #9 · (Edited)
All dialed-in !

I got it all dialed-in, and a test ride on Sat proved success; quiet & no drag. :thumbsup:

In my case, I needed the lower roller to be shifted towards the non-drive side by 2~3mm.

Below are what I did to squeeze this in, just in case anyone is interested. (See diagrams below.)

#1 - Chris at Truvativ/SRAM and his tech team provided me with a trick that I can firmly push the "tapered bushing" completely flush into the roller, so none of it is sticking out. In contrast, out of box, it's protruding out of roller by about 2mm by default. (Thanks, Chris!)

#2 - I replaced a 2mm washer (between roller & plate) with a 1mm one that I happened to have handy.

Together that's 3mm towards the non-drive side, and it works great on my bike.

Finally, I did one thing with the upper Guide Block piece. Even though I tried not to over-tighten, the bolt head wanted to go thru the plastic block. So, I found some chain links ($0.71/ft at Lowe's), and it fits right inside like it was made for it. (See pic below.)

Cheers,
- PiroChu
 

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