Author Topic: Brooks b17 - replacing nose bolt  (Read 486 times)

Brooks b17 - replacing nose bolt
« on: February 15, 2020, 08:14:23 am »
Need to replace the nose bolt, have bits. Trouble is, I'm not sure what goes where. Can someone share a photo of the nose bolt in situ?
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Tim Hall

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Re: Brooks b17 - replacing nose bolt
« Reply #1 on: February 15, 2020, 08:25:51 am »
There are two ways you can get exercise out of a bicycle: you can
"overhaul" it, or you can ride it.  (Jerome K Jerome)

Re: Brooks b17 - replacing nose bolt
« Reply #2 on: February 15, 2020, 09:25:04 am »
Thanks, perfect
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Tim Hall

  • I want to eat the fleeting shade of your lashes
Re: Brooks b17 - replacing nose bolt
« Reply #3 on: February 15, 2020, 10:28:43 am »
No bother.

I had to crawl from my bed all the way to the corridor, a whole 3m away, to get that. Before breakfast too.
There are two ways you can get exercise out of a bicycle: you can
"overhaul" it, or you can ride it.  (Jerome K Jerome)

Re: Brooks b17 - replacing nose bolt
« Reply #4 on: February 15, 2020, 10:39:54 am »
I will be intrigued to understand how you replace a standard B17 nosebolt.  My experience is that without a level of saddle dismantling it is impossible so I have developed an alternative using the nosebolt from a B17 titanium and a round file.

It is not for everybody but I have half a dozen modified saddles out on test and so far none has shown any problems after over a year.  One is used nearly every day.  I plan to put another dozen into circulation in the spring.

Video or photos would be appreciated.

Re: Brooks b17 - replacing nose bolt
« Reply #5 on: February 15, 2020, 11:11:52 am »
I used a machine screw with phillips head - something similar to the follow in M8
google images link



the head needs to be too big to go through the cup at the nose end of the saddle, and the phillips head remains accessible trough the hole in that cup.
Has done about 10,000 mile since that bodge, which is longer than the original brooks part did.



clearly not as snug a fit as it could be, but that seems to make no difference to in functionality

Re: Brooks b17 - replacing nose bolt
« Reply #6 on: February 15, 2020, 11:45:32 am »
I've used machined M8 bolts/nuts to replace Brooks nosebolts.  If you choose well, you can access the hexagon in a machined allen bolt head and this makes adjusting the saddle tension much easier.

However most brooks models don't use a metric thread in the nosebolt so the nut often needs to be changed too, and the nut won't fit properly unless it is machined (eg as per photo in post above; with this arrangement the threads on the bolt are soon worn/bruised and this can inhibit further adjustment). However if you get the machining right (with a small taper on the reduced diameter portion of the nut) the nut doesn't need to be held when adjusting the tension.

You are probably thinking "I can't machine stuff". Well, if you have (or can borrow) an electric drill and an angle grinder, you can machine stuff like this; just hold the bolt in the drill chuck, set it  (clamped down) to spin at some highish speed, and bring the angle grinder to bear. You will soon find that you can remove material quickly and easily, whilst keeping the part nicely circular still. Use a thinner disc for making smaller cuts and radii. Polish/deburr as necessary.

Additionally you don't need to machine anything if you don't want to; as mentioned in a post above Brooks Ti parts can be made to fit other saddles (which may require enlarging the hole in the nosepiece) additionally there are also parts from other leather saddles (eg the ones sold by spa cycles)
 https://www.spacycles.co.uk/m2b0s204p0/Parts-and-Accessories/Saddles-Leather
which can be made to fit too.

BTW IIRC the spa nosebolts may be easier to fit than Brooks ones; ISTR the nut can be taken closer to the head of the bolt, thus making the thing shorter and easier to fit to an unstretched saddle.

cheers

Re: Brooks b17 - replacing nose bolt
« Reply #7 on: February 15, 2020, 01:57:04 pm »
I got the nose bolt into the cup with a bit of grease on the end. Trick was to use body weight, leaning onto saddle from top, with bolt resting on wood.

Difficult bit was getting it right into the hole.

In the end did it with hole in adjustable wrench around bolt, squeezing saddle sides together and body weight again.

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Wowbagger

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Re: Brooks b17 - replacing nose bolt
« Reply #8 on: February 17, 2020, 11:15:34 pm »
I've done this a couple of times. I find that the job cannot be achieved until the bolt and surrounding parts are liberally lubricated with loud profanities.
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