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73mm Road crank, do...
 

[Closed] 73mm Road crank, does it exist?

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I'm currently running an "old" XC hardtail as a road bike. By and large it works well enough but the issue is I run out of gearing at the top.

It's setup with a 48t on an xt 104bcd crank and that seems to be as big as I can get.

A road crank set (or anything really) with a 52 or something would be great but...
... It's a 73mm BB shell so a normal road ht2 won't play.

Can anyone point me in the direction of a bigger 104 bcd ring or a set of cranks that will work (current cranks, I don't want to replace old gear with stuff similarly into obsolescence)


 
Posted : 28/05/2020 3:42 pm
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https://en-gb.facebook.com/MiddleburnbyBETD/


 
Posted : 28/05/2020 4:10 pm
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Try spinning your legs faster? That's the cheapest solution, and 48/11 at 90RPM is somewhere around 30mph.

Alternatively, fit an 11 tooth cassette if you don't have one.

Or, just fit a road double chainset, it could well work, providing there's plenty of clearance at the chainstays. You'll need to remove your BB spacers though (presuming you're currently using Shimano HT2).

Ignore that, missed the 73mm shell width.


 
Posted : 28/05/2020 4:18 pm
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52 you said?

https://www.ebay.co.uk/itm/SNAIL-104bcd-44-52t-MTB-Road-Bike-Chainring-Narrow-Wide-Chainwheel-Crankset/264562430903?hash=item3d992653b7:m:mSiYqUtdeIiKGWC3wn4Vh_g

If you do not want NW TA Chinook at 50T https://www.wiggle.co.uk/ta-104-pcd-chinook-4-arm-mtb-outer-chainring-48-50t/

Shifting might be a bit slower without ramps and pins but was working for me OK on 48/38 crank...

Cheers!
I.


 
Posted : 28/05/2020 4:57 pm
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Just go old school square taper chainset and you can go for any BB width you like.

Spa Cycles double chainset with a 52 ring is £65 so cheapish and functional.

Not a flash or ultralight solution but more than functional.

You can go cheap and old or lighter and flasher too. Worth considering for a commuter steed.


 
Posted : 28/05/2020 5:06 pm
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Shifting might be a bit slower without ramps and pins but was working for me OK on 48/38 crank…

Hmmmm I'll take a look at that then thank you.

Try spinning your legs faster? That’s the cheapest solution, and 48/11 at 90RPM is somewhere around 30mph.

Yes, that's true, I also really really hate spinning.


 
Posted : 28/05/2020 5:12 pm
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Bastard of a job, but you can use a BB facing tool to mill down to 68mm, then have the choice of anything you want - assuming you have chainstay clearance for road sized rings and Q factor?


 
Posted : 28/05/2020 5:14 pm
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You can go cheap and old or lighter and flasher too

There's such a thing as a not old square taper/octalink crank? I thought they were old hat before the intention of gas lights


 
Posted : 28/05/2020 5:15 pm
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Bastard of a job, but you can use a BB facing tool to mill down to 68mm,

Ah yeah. Ti frame. That would be a pig.

I'll take a look at "old" bb types. Never even occurred to me folks still made them.

(and at the middleburn stuff, there's a 50t listed which might just be big enough. Annoyingly an xd cassette would solve the issue and 10/48 was fine on flat bars. The issue the is I never used half of it and now if I tried it wouldn't fit my mech etc etc)


 
Posted : 28/05/2020 5:19 pm
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Q factor?

Massively overrated thing... It is noticeable only for first 30-45 minute of riding after crank change. After that you are just forgetting about it and cranking up...

chainstay clearance

That is probably much more important factor...

Cheers!
I.


 
Posted : 28/05/2020 5:23 pm
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Ah - Ti. Yup - facing is a no-go!

Re Q-factor - it was the chain stay clearance of the narrower Q-factor that I was warning about. Easy enough to widen either by cleat placement and/or pedal spacers.


 
Posted : 28/05/2020 5:31 pm