V20c chain line question

[corelli]

I sent this issue to Robert but was wondering if any members have encountered similar issues. Any thoughts you have would be appreciated!

Hello Robert,

A couple of questions. I am building up my v20c frameset using your Croder short crank system in a 1x11 arrangement--not the norm, I know.

The chainline seems way off and appears to line up with the 9th cog on the cassette. There is a 1mm spacer on the drive side spindle. I think that is required. So I see no way to bring the chainring inboard. The chainring included has a 3mm offset. Not sure why a 6mm offset chainring was not specified instead--but even that would not come close to center on the cassette

Another frustration is the bottom bracket. Spent hours searching for a socket. There is nothing I can find that fits this. The only thing I could find was a hand wrench I could order out of China. Not sure how to set appropriate torque with a hand wrench.

Thanks for the help,

Jon

P.S. In case you are wondering, I was able to assemble the above with a Park Tool socket Could only torque to about 15- 20nm before it slipped.

 

[RojoRacing]

A lot of crankset/BB kits come with a plastic 3mm spacer that generally is specified for the drive side. Honestly, it's just there to take up space on narrow BB shells and can go on either side of the BB. The important part is that the correct amount of preload is applied to the bearings.

When you say 9th cog, do you consider the smallest or largest as the 1st cog?

There is a tool to make T47 easier to work on without slipping.

The real problem with T47 is when you use a socket and ratchet because the vector at which you apply force is too far outside the actual piece, so it wants to rotate out. If you use a thin stamped tool, your pressure is in line so less likely to slip.

 

[sixty-six]

I used a praxis chainset with 160mm cranks, they come with an option on the spiders 2x and 1x, the bottom bracket is supplied with a few spacers and the spiders are designed for correct chainline and rings for 1x or 2x . I went with praxis because I have them on throw of our other bikes and they have their own tools for bottom bracket fitting with a torque wrench.
1x is finicky, I have found it's worth spending a little extra to get the exact setup rather than try to bodge something else...oh and only use specific 1x rings.

 

[corelli]

Thanks for the responses!

Currently, there is a 1mm spacer on the drive side. Croder's directions were unclear and I thought it was required. Sounds like this spacer is not needed there--correct?

Right now, my chain line is between the 8-9 cogs (smaller cogs).

You are correct on the socket and force vectors--gotta love physics!

Croder does make a 6mm offset chainring (currently have 3mm)--so that may help as well.

Is there such a thing as a spindle that might be a few mm shorter? Looks like I have room to spare on the drive side.

I will check out Praxis as well.

Thanks guys! I welcome any other thoughts on squeezing out a few extra mm!

 

[RojoRacing]

Thanks for the responses!

Currently, there is a 1mm spacer on the drive side. Croder's directions were unclear and I thought it was required. Sounds like this spacer is not needed there--correct?

Right now, my chain line is between the 8-9 cogs (smaller cogs).

You are correct on the socket and force vectors--gotta love physics!

Croder does make a 6mm offset chainring (currently have 3mm)--so that may help as well.

Is there such a thing as a spindle that might be a few mm shorter? Looks like I have room to spare on the drive side.

I will check out Praxis as well.

Thanks guys! I welcome any other thoughts on squeezing out a few extra mm!

Without that 1mm spacer axel will probably bottom out before the BB bearings are preloaded so yes you need it, but what side it goes on is generally dependant on the frames chainline. You can simply move it to the other side and reassemble while taking extra caution around frame and spider clearances. As you tighten on the crank, stop a few times as you go to rotate the crank a full revolution to ensure nothing hits or binds. When you crank bolt is completely tight you must have some side to side play, if there is none you did something wrong. That last bit of play to removed with the preload adjuster ring. As long as you're doing that you should be safe.

 

[Robert Holler]

The above is great advice. The BB cups also need a spacer for the V20C. The corder set was primarily sourced for the S40 and there haven't been many people try it on the V20C. For the wider shell of the V20C likely a 6mm offset is needed, which we do not have, unfortunately. The only other people I know of that have put a Croder on a V20C didn't use the 1x as they sourced their own 8 bolt double rings as they were wanting to maintain the double ring setup.

Robert

 

[corelli]

Just a bit of follow up. One issue I was having was the fact the BB would not fully seat into the shell. I was sent a second boom/shell and this had the very same problem. Extremely tight on the drive side. I also noted that the Croder BB threads were longer than the shell threads (a SRAM BB had shorter threads by way of comparison)

Robert was kind enough to re-tap this for me and confirmed that the factory tap on the drive side was probably quite worn, hence the shallow cut. I mention this just in case someone else is having similar issues--hopefully you will have a local mechanic with a T47 tap (unlike me)!