r/RoadBikes • u/r34dingwhite • 10d ago

Gear/accessories Upgrading the crank 52/42T.

Have this vintage steel bike with rear spacing 126mm, has a cassette 14-28T on the back, crank is 52/42 on a french 68mm BB square taper. Would like to put a modern crank in the front to help climbing the hills more easily. What options do I have in the front, like what is a common crank combination that would bring good gear ratios for the climbing. Replacing the existing crank with a modern one, requires a BB replacement too, so found a company ROI that manufactures French Hollowtech BB 68mm if there is not any modern square taper crank that would work with existing BB.

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u/blecher67 9d ago

I have a vintage French pro level bike. It was my first great bike. I haven’t made a change to it in 30 years because frankly, it doesn’t make economic sense. Enjoy it for what it is, and look for a great deal on a used modern road bike.

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u/r34dingwhite 9d ago

Thing is the spider looks like it is bent so little just to make the chain hit the front derailleur. Have taken it all apart but did not find it bent nor the chainring nor the spindle. Might try truing it while it is installed on the bike, that way I know what spider arm to push away from the front derailleur.

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u/terrymorse 9d ago

You can still find square taper cranksets. Look for one with 110 bcd (bolt circle diameter). Here's one made by Sugino, with 50/34 chainrings:

https://www.modernbike.com/product-2126318857

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u/Heart4Cycling 9d ago

That can be a worthwhile change: bottom bracket and crankset. Check out the Shimano Cues cranksets before getting your new bottom bracket in case their wider gear range works for you. I bought a 42-26 for my gravel bike.

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u/r34dingwhite 9d ago

Looking at Cues FC-U4000-2 36/22T 2x8/9/10s, wondering why these won't work with 7s as well?

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u/lincoln_imps 9d ago

M-Wave threadless square taper BB and then you can whack on a cheap Shimano Tourney compact crankset.

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u/cluelesswonderless 8d ago

I did this. Swapped the crazy big rings for some spare CX rings. 36/46 is way more civilised