Compact road crank. Any reason why not?

[RadNomad]

I’m considering putting a new compact (50/34 Sugino Mighty Tour) road chainset on my ‘96 LavaDome for faster road riding. Any reason why i shouldn’t / couldn’t?

Sugino’s suggested BB is 110mm which is same as the LavaDome’s. The SRT400 front shifter is the multi click type so by limiting the front derailleur screws i reckon i should be able to mod it for shifting only 2 chainrings without dropping chains. Rear derailleur is 7 speed XT. Others on here reckon the slightly thinner modern front chainrings should be ok with a 7 speed chain.

It seems this should work. Have i missed anything? Has anyone tried this?

 

[legrandefromage]

Just run a narrower chain

 

[Titiritero]

Re:

I've read (but never tried myself as my only drop bar runs on friction) that mtb front shifters don't work well with road cranks, different spacing or something. This is only for Shimano, SRAM uses the same for road and mtb.

So investigate further before you commit...

 

[hamster]

Re: Re:

I've read (but never tried myself as my only drop bar runs on friction) that mtb front shifters don't work well with road cranks, different spacing or something. This is only for Shimano, SRAM uses the same for road and mtb.

Front shifters for Shimano road have a different cable pull.
Using MTB front mechs can be a problem with fat seat tubes as the chainset is closer to the centreline. However, with your steel frame it will run fine.

 

[one-eyed_jim]

One possible sticking point is clearance between the chainstay and the 34t ring.

A 34t is (obviously) a bit bigger than the 32t middle you currently have, and will sit a touch closer to the centre line of the frame. Road bikes are typically designed for a slightly narrower chainline than mountain bikes, and the inner ring of a road compact double will sit slightly inboard of the chainline spec', while the 32t of a compact triple should be dead on centre.

https://www.sheldonbrown.com/chainline.html

Frames vary in that area, but you may need to consider spacing the bottom bracket over a couple of mm with a spacer under the fixed cup. See how you go.

 

[legrandefromage]

Heres my take a few years ago

 

[hamster]

Should be fine. I ran a Campag 39/53 with stock Campag road BB on my Cindercone.

 

[Koupe]

Not sure why you'd need road cranks? I used to run 52 rings on DX cranks with no issues, other than losing the granny ring.

 

[hamster]

Not sure why you'd need road cranks? I used to run 52 rings on DX cranks with no issues, other than losing the granny ring.

Because they were there?

 

[Woz]

Agree with one-eyed_jim - chain ring clearance may be an issue. There may also be an issue with foot clearance
due to the lower Q-factor depending on your own pedals and how you position your foot.

Simply try fitting it to see how it all mates togeter; you can also increase the BB width if necessary.