Customised Bike Bits (Updated 26-07-04)

I originally started G-Sport to sell custom stuff I had made for my own bike. Most of the stuff is not practical to bring out as products but is still good stuff. The following pictures will show you some of the bits I have made for my own bike as well as a quick description of how and why I made them. This page takes a while to load but you can be reading the words while the pictures come down...It is all on one page for simplicity.



OK. I am just rushing this on to here so expect some poor presentation....

Much the same as the old frame below, but I managed to cut the weight back from 7.5lbs to 6.5lbs whilst still be ludicrously strong.
T45 hand made in Sheffield and TIG welded by Stuart. Total bike weight is 31.5lbs.

74.5 degree head angle
71.5 degree seat angle
20.25" Top Tube  1,3/8" 17gauge 0.056"
Down Tube 1,1/2" 18gauge 0.048" with gusset
14" chainstays as set-up.
11.7" Bottom bracket height
YORKSHIRE bottom bracket with Spanish BB bearings in nylon6 cups.
Left hand chainstay grind guard, angled AD bosses.


hover hover, its just a picture...

OK this is my previous bike set-up. As you can see it is pretty much all custom stuff. I grind on the left and just run two left pegs (which are on the other side here). The whole thing weighs just under 33.5lbs at the moment which isnt bad. The frame is TIG welded from T45, the chainstays are box section aerospace certified and the rest is round commercial grade stuff. I have been riding this frame for about 4 years now and as you can see it is holding up pretty well. The back end is set at 14.25" and the top tube is about 20.5". I run a 36-13 gearing.

I do a lot of grinds and icepicks so the 
back end takes a lot of hits. The hub is a G-SPort homer 14 tooth with 9/16" bolted axle (see catalogue).
The peg in this picture is a stainless one that I
previously jammed into my hand and I 
have now changed to something else. 
The plate welded to the bottom of the
dropout makes grinds really smooth 
and the G.L.A.N.D. spoke protector was 
the final pre-production prototype (see catalogue). Now replaced with a production model because I wanted a black one...
Between this lot I can grind forever.

If you have ever lost a peg during a grind you will know that it laces your chainstays when they hit the edge. This thin bit of stainless welded to my chainstays has taken a lot of hits and done an excellent job of protecting the even thinner T45 beneath. In this picture you can also see the Modified BSD sprocket that I ran. These are seriously good, made by BSD in Glasgow and 10mm thick. You can also see the old position of the brake mounts under the seatstays. I had to shift them from there after I built it because they hit the chain....

This view shows my old rear brake. This was a modified U'brake that I ran for about 3 years. The pivots were bored out and sleeves glued in which take 2 sealed cartridge bearings each. The springs had to come out to make room for this and I replaced them with a single tension spring accross the top of the arms. This was a bit of a bodged job and is coming to bits now but it has worked very well and has needed absolutely no maintenance over its life. The exrtra long straddle is a piece of mountain bike braided inner cable held in the pinch bolt and with a nipple clamp (see catalogue).


This is my new back brake. Just a standard Odyssey Evolver. Because of my angled bosses I had to cut a large chunk off the bottom of each arm to clear the stay. It works fine and the Odyssey 1by4 brake blocks seem very good too.
You can also see in this picture that I got rid of the old cranks in favor of a pair of Primo Powerbites. They certainly seeem pretty good so far and the extra stiffness is very noticable. The bosses did come undone when I changed pedals but they went back in no problem so who cares...

wide angle.....
I have now fitted a 13 tooth Odyssey freewheel to my back hub so the BSD 38 sprocket needed replacing. I got this Odyssey 36 cheap but thought it was a bit heavy. I skimmed the outer portion down a bit on the lathe and enlarged the existing lightening holes to save more weight. I have also started running the Primo cranks without the end bolts, this saves a couple of ounces and has no discernable effect on their performance... as long as you keep the bolts handy for setting up..

This is probably the modification I get asked about the most. I have always had problems with lower gyro cables, even when I ran two seperate ones. They would get kinked and need lubing all the time. Eventually I started thinking of ways to get rid of them entirely. This little baby does the job. I have run this mechanism for the last two years with zero problems. The links are cut down spokes and nipples and the plates are just cut from thin aluminium. The bottom straddle cable is super long and runs all the way from the brake to this mech and back. I would love to be able to produce these but there are just too many frame variations. You can also see my old top gyro plate which was machined from 6mm aluminium. Now replaced with gyro tabs on the stem.

Having made myself a Cartridge bearinged rear brake could the front be neglected? Of course not. I couldnt find a brake suitable to modify so I had to work out a way to make one on a lathe. This was the result. It works super good, canti's are great for the front, the bosses are welded on in a place that causes less stress, you dont need the big loop of cable and it weighs less.
This is totally the way to go if you like simplicity, the outer cable housing stops at the fork top bolt and the inner just runs down the steerer and out through an angled hole. Although you would expect this to be a nightmare to set up it is actually dead easy. The brake blocks are held on with nuggets (see catalogue).
I always bung a jubilee clip (hose clamp) round the headset cup BEFORE it breaks.

I finally cut my bars down. After years of using super wide bars it took a lot of getting used to but now I love it. These old bars still looked pretty wide but they were just over 24" wide. To do this on my faithful old G-Sport Wunderbars I had to machine the brake levers out to 1,1/8" and bend the levers quite radically. It actually worked perfectly and it is now impossible to cut my thumbs on the levers. However I have now changed bars again...

Eugh!!! 6 piece bars !!!!!
These are my latest bars. 6 piece T45 construction with a 2.5mm thick EN24t clamp tube. Uprights are 1,1/8" diameter as before so I could transfer brake levers straight accross. Grip sections are "butted" from 16 gauge at the weld to 18 gauge at the outside end. Fairly small bars, should be incredibly strong, and under 32 ounces.
The new stem is still in development so blacked out for security reasons.

Here you can see the top bolt, old stem and cable arrangements. The top bolt threads directly into the top of the G-Sport prong fork's machined EN24t steerer tube. This bolt holds the headset tight and will not slip, it also holds the end of the outer cable for the front brake. The old nimrod stem had a removable back as well as front to make it clamp really tight and to make taking the bars off for flights etc. much less hassle. Both the forks and the stem are now discontinued unfortunately.

Running two top gyro cables is always the way to go but can be tricky. My old solution was to drill the lever through and clamp two ordinary cables in a slightly modified pair of nipple clamps (see catalogue). What I did was to set the cables to the right length then clamp a nipple clamp to each one. The nipple clamps had had the hexaganol heads sawn off. When they were tight I inserted another grub-screw into one of the nipple clamps so it stuck out the top then screwed the two clamps together with it. Then I inserted the barrel adjusters into the home-made little doubler plate. While I was at it I reamed out the levers and fitted some more sealed cartridge bearings...

This is my new brake lever set-up. Its a stock Tech 99 drilled out to take a slightly modified Nipple Clamp holding two cables. The Nipple Clamp was designed for older thinner levers but these means that it can be nicely countersunk into levers like this leaving absolutely nothing sticking out. The two into one part is simply an old gyro cable splitter cut down.

This is my seat. Crap eh? NO. these seats rule, there are no rails to bend and it costs like £5. Light weight and best of all if you land with it up your arse it hurts much less than a hard plastic one. You would be amazed how much hammer these take. I have only got through about 1 of these a year. Dont waste loads of money on fancy seats....
The post is one I knocked up out of T45...

backside !!!!
Finally, a view of the other side of the bike. Not much to see here but you can appreciate better how the angled brake bosses make for an almost perfect cable line to the back brake...


Well that about wraps it up. If you want to know anything else just mail me.

Copyright © 2001-4 G-Sport.  All Rights Reserved.   The content of this website may not be reproduced or transmitted in any form in whole or part without the written permission of the owner.