Dear all
Having sent my entry off for the Lands End I am now thinking how on earth to get up Hoskin Hill. I have only been up it once - that was without a restart. My current thinking is to let the tyres down even further as the hill is very smooth(!). This brings on a possible problem of the tyres slipping on the rims so does anyone know anything about tyre security devices. All I have been able to find out so far is that one type employs a sort of triangular lump which clamps the tyre to the rim from inside (how would you fit it and how does the tube fare?) Another type seems to be a captive nut on the rim through which a pointed bolt is screwed into the bead of the tyre!
Had a good run on the Exeter, Failed Tilerton (stopped in the top of the box and couldn't get away, rolled back a foot a drove out!) climed Woostern - restart a lot lower this year, and the best bit - got up Simms - straight up the middle. Ands of course failed Higher Gabwell. Next year........
Mike Warnes
I use M8 nuts welded to the rim through which I install pointed cap head (Allen) screws. I'm not sure that they work that well as I still experience some tube pull from time to time. But who can say what would have happened without them! The screws are not that easy to remove sometimes (due to water/mud ingress) - this would mean at least 10 minutes extra work for an on-event tube change. Hex head set bolts would probably be better - I'm planning to change to these soon. It's also difficult to judge how much penetration into the bead is required. Too little and they will be ineffective, too much and they can split the bead (this has happened to me once - on the way home from the Edinburgh at about 50mph - the tyre exploded at the bolting point). Devices like this probably contravene construction & use regulations.
ReplyDeleteI use M8 nuts welded to the rim through which I install pointed cap head (Allen) screws. I'm not sure that they work that well as I still experience some tube pull from time to time. But who can say what would have happened without them! The screws are not that easy to remove sometimes (due to water/mud ingress) - this would mean at least 10 minutes extra work for an on-event tube change. Hex head set bolts would probably be better - I'm planning to change to these soon. It's also difficult to judge how much penetration into the bead is required. Too little and they will be ineffective, too much and they can split the bead (this has happened to me once - on the way home from the Edinburgh at about 50mph - the tyre exploded at the bolting point). Devices like this probably contravene construction & use regulations.
ReplyDeleteI run a class 8 Troll with 15inch MGC wire wheels. The wheels have been modified with 6 x 8 m.m. nuts welded to the inside of the inner rim. I use 20 m.m. long hex headed bolts and grind the ends to a point. I assemble with spring washer and a spot of 'copperslip' grease on the thread and they are fast and easy to remove with a 13m.m. socket and a three eighth ratchet drive. The nut is positioned so the bolt point just penetrates the inner bead, it leaves a small mark on the bead. You do not even have to fully remove the bolts when changing tyres! I have run this setup for 3 years and despite going down to 4 p.s.i. for some sections have never had the tyre slip on the rim. As a further safeguard I use undersize tubes (155 x 14) and get them fitted with tractor valves. The valve has a retaining nut to prevent the valve pulling back into the tyre, its a bit like a motorcycle or push bike set up. Hope this helps, we cleaned Hoskin with this set up last year!
ReplyDeleteWell in sporting trials I know some poeple have gone tubeless... Everyone has security bolts in the rims as we run down to about 1.5psi sometimes.
ReplyDeleteI currently run with tubes, but shall probably go tubeless over the summer, if I find time to do it!!
The Fack brother's have been running tubeless for about four years now, and when I have been with John we have never had a puncture.
The way to do it: (I believe)
Weld a washer into the rim and fit a tubeless valve
Fit tyre
Blow up and fit security bolts using fibre washer on each
Then deflate
Remove the valve
Fill the tyre with tyre sealant from Halfords or somewhere like that
Refit valve
Blow up to tyre
Dunca
Erm, inner tube? whats that?........
ReplyDelete