# Wheel axle, nut size?



## gambatte (31 Mar 2014)

Should be an easy one.

Eldest lads shot up over the last year. Not only are we having to budget for a 12 year old who’s now eating more than me, we have to replace all his clothes and I realised there’s going to be no point getting his bike out.

I put it to ‘max’ on the seat and bars last year. I’ll pass it down to his brother.

So I’ve been given an old bike to do up. Definite ‘BSO’ but it’ll do him, for now. There’s a fair bit of tinkering to do. Not least that the LH crank wasn’t fully tightened and has got mangled by the square taper drive... having the previous owners 20st put through it (she is a short, BIG lass!!) won’t have helped.

Anyway, one of the things I noticed, no quick release hubs just nuts. One on the fronts missing. I’m at work and I can ask maintenance to get hold of one. Thing is... what’s the most likely standard size?

Thanks in advance.


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## compo (31 Mar 2014)

My MTB nuts do up with a 17mm spanner, front and rear. Some bikes have different sizes front and rear. There is also the issue of the thread type. A standard metric 17mm nut might screw on OK, but then the thread may not be the same so it wont. Your best bet would be to give the other nut to your maintenance man and ask him if he can match it up.


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## RecordAceFromNew (31 Mar 2014)

Axles are usually in 3 thread patterns: Italian (9mm x 26tpi front and 10mm x 26tpi rear), Japanese (9mm x 1mm front and 10mm x 1mm Rear), Taiwanese (9mm x 1mm front and 9.5 (3/8”) x 26tpi Rear).


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## hoski (31 Mar 2014)

I would advise taking the other nut as comparison. I have had at least two different axle diameter/thread variations - and BSOs can sometimes throw a curve ball with this kind of thing.


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## gambatte (31 Mar 2014)

Ta, I was figuring the cheaper end have a common thread.
I tried one of the nuts from the front of his old bike and it fit. I need to get it back as they’re all black and I know his younger brothers going to want ‘his nut’ back.
Should have brought it in really...
Just figured they all are probably M10 with a standard pitch.
I’ll grab one from maintenance, see if it fits. If not, bring the proper one back tomorrow.

Ta again guys


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## gbb (31 Mar 2014)

One from your maintenance dept wont work, the standard thread's too coarse.
TBF, i dont know what size they are...but theyre not standard M10.


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## Tim Hall (31 Mar 2014)

If it's M10 it'll be M10 fine (M10 x 1.0mm, rather than the more common M10 x 1.5mm).


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## gambatte (31 Mar 2014)

We'll have M10 fine, standard and coarse (Precision engineering company) Possibly nyloc versions too. Just got to pin down which type....


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## RecordAceFromNew (31 Mar 2014)

gambatte said:


> We'll have M10 fine, standard and coarse (Precision engineering company) Possibly nyloc versions too. Just got to pin down which type....



Chance is you are wasting your time. As I have already indicated above, front is practically never 10mm.


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## gbb (1 Apr 2014)

Wiki states old axle threads were BSC..British Standard Cycle..and many cheaper axles made in china still use BSC.
(Id put a link up but im on the tablet)
Having worked in engineering since 1977 ..imperial threads were still in use (just)..and neither BSF or UNF, both fine threads, fitted bike axles...i tried


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## Peterlomax (16 May 2015)

This may be a little late to help you bods (I've just joined) but I'm trying to rebuild an old bicycle, about 1905, and it has a front axle with a 9.5mm x 1mm pitch thread.
I too thought 'never heard of it', must be 3/8 x 26 cycle thread. 3/8" = 9.525 mm and 25.4 tpi is not far from 26 tpi. Very close, but unfortunately not close enough, because I'm not able to fit the cones onto an English axle. If I can't find an axle I expect I'll have to make one, unless, of course, some kind soul has one and is willing to part with it


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## sidevalve (16 May 2015)

Right about the cycle thread [26 tpi] certainly not metric coarse. Should be easy enough to get from any oldish bike shop. If not try a classic m/cycle specialist as many old bikes [BSA for one used cycle thread as they mostly made cycles at first].


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