Looking for a new crankset for my roadrat singlespeed. Fed up with the gxp bb not lasting long, was thinking of Shimano 105 cx50, anything else I should look at?

I use square taper BB and then a Sturmey Archer crankset from Charlie, works for all I’ve needed it for, including a week long tour around Holland..

Cheap and Strong, may not be bling but I’d rather have function

An old road triple with single chainring bolts.

Spa cycles touring triple – £20 and a UN54 BB

never considered square taper – is it easy to fit / remove ? cheap and reliable are my main requirements.

Why a triple, can you not convert double’s ?

Yes and yes. you need a couple of extra tools, which you can pick up cheap. plenty around that aren’t being used.

Cheap and reliable is what Square taper does. I’ve got an 18 y.o. Shimano UN72 BB that’s done 20,000 miles in 3 different bikes. I’ve just fitted it to a fourth and it’s still spinning perfectly smoothly.

You can space a double, but a Triple has a centre position which is in the middle already.

Depends if you’ve got a SS specific rear wheel with a fixed sprocket position or a cassette freehub body with spacers. Cassette freehub body with spacers means you can get what you want up front and tweak chainline from the back. So if you might convert to 2×10 or something later, you can get the double.

If your chainline is fixed at the back by a SS rear wheel, you’ll have to look carefully at cranks and BB spindle lengths (if you’re going Square taper) that will give you the right position up front. Chainring bolt spacers will allow you to tweak a little, but only in one direction!

thanks – I have freewheel with DMR Single Speed Converter Kit.

18 years!!! going through a bb 3 times a year at the moment.

Yup! 8) take that, HT2! Loads of ST enthusiasts/curmudgeons for that reason, all happy to tell you that the ST BB is the high point of BB design, and every “advancement” since has been another step back to decrepitude and built-in failure and obsolescence.

Why a triple, can you not convert double’s ?

Sorry – I missed the singlespeed bit!

For gears a triple works better because you can use the middle chainring position which gives a better chainline in the highest and lowest gears at the back. Otherwise you’re effectively cross chaining.

But perhaps a triple would give you a better chainline for you SS?

I have never, and will never, get the square taper love. Yes, the BB bearings lasts forever but the cranks creak and the spindle flexes. I used them on mountain and road, fitted by me and by my LBS. HT2 is/was a huge step up in performance and, once the initial reliability had been sorted, in reliability too.

So yes, to answer your question, how about an Alfine crank paired with an Ultegra BB (£10 from Merlin). That’s what I’d do anyway.

Square taper ftw, I’m using an old XT with the 44 in middle position, gives a good chainline with a ss rear wheel in a Steamroller. I can’t remember the spindle length I used though.

Alfine crank looks interesting, can you remove the chain guard?

can you remove the chain guard?

I’d think so, yes. You may need shorter bolts or some spacers, but it looks like it’ll come off.

how about an Alfine crank paired with an Ultegra BB

The Alfine has a bit of a quirky chainline iirc, and I don’t think the DMR kit has many options for tweaking cog position.

old double or track c/s is nicer than triple. A chain ring inside the spider is a foul looking thing. Just like modern double MTb c/s

lunge –

all happy to tell you that…

I didn’t say I was quite in that group! Foot in the door maybe…

Got HT2 on Fat, monstercross and hardtail, SqTa on the tourer/commuter. No creaks, the cranks are older than the BB, and the frame’s very compliant steel tubing about the side gauge as my thumb, so BB spindle flex isn’t something I’m going to notice!

I can see it wouldn’t be top of the list for a super stiff sprinting machine, but for cheap/simple, low maintenance workhorse bike, ST ticks a lot of boxes.

my XC MTB 2009 came with square taper.
I had worn the cassette and chain rings by 2014 but the BB was fine.
took the opportunity to “upgrade” cranks and BB to hollowtech2 while replacing Chain rings.
Two years later needed new BB yet the square taper was fine after 5 years.