Gearing for LDTs

[ian640]

I'd like to use my TFS more in LDTs (events like the Wygate and Witley 100 and not the Land's End). At present it's geared for single venue trials. If anyone else uses their Greeves for LDTs I'd be interested to hear what front and rear sprocket sizes they use, and in particular the size of the rear sprocket they use for LDTs compared to the one they would use in single venue trials. How many less teeth on the rear?

Thanks.

[John Wakefield]

Is this event you are planning to do? https://www.youtube.com/watch?v=yhM2pTU5x04 As this is mainly an off road event with some trials type sections included i would think standard trials gearing will be OK. I assume the special tests are the only 'speed' part of the event, so a good performance in the nagery stuff could compensate for lower performance in the speed tests. Best to enter one event and see how it goes you can then gear up (or down) by a few teeth on rear sprocket for the next event.
In actual fact a one day trials bike would be more suitable than a highly strung enduro bike. I competed in the 1970's in the Welsh 2 day trial on a Bultaco Sherpa geared up one tooth on gearbox and a larger tank. I also competed in the Aldermaston Nomads long distance ISDT type trial also on the Bultaco, that was about 100 miles with quite a bit of road work, fast green lanes & time checks. I wonder where PCE4J is today, according to DVLA last tax expired 1st March 1982

[teamferret]

I would go up one on the front sprocket so about 5 or 6 smaller on the rear

[ian640]

Thanks. I've actually done several LDTs on the bike, and it's been great in the sections, but found the gearing a bit low for the road stages. I think I will try going a bit smaller on the rear sprocket.

A friend has been encouraging me to attempt 'the Welsh' on the TFS . Not likely but we will see.

I don't believe Aldermaston Nomads runs an LDT anymore, but they do run their excellent Three Stage Trial that's becoming something of an annual pilgrimage. Now I think that would be on the cards on the TFS...

[John Wakefield]

'I don't believe Aldermaston Nomads runs an LDT anymore'
No that superb event stopped in the 1970's, the Rallies act was the problem as it required an RAC permit owing to the timed stages using public roads. It was always used as a selection test for the British ISDT team.
With regards to your gearing, with events like the Wygate and Witley 100 that have observed sections you need to maintain a low enough bottom gear to do the sections, whilst keeping a high top gear for the fast stuff. In ISDT / Enduro type events there are no observed sections so you can gear up a bit more to keep revs down in the fast stages of the event. With only 4 gears in a Villiers gearbox it is difficult to get ratios right for all parts of the event. The wide ratio trials ratios with a big jump to top are not well suited to these sort of events.

[John Gresty]

Agree with John here. I had my machine (1961 TDS) set up for observed section trials by fitting gears which worked well but had a large jump from third to top. When I rode it in some twin shock enduros I had a smaller rear sprocket made, but still suffered with the gap between third and fourth. Had to flat out in third before I could change up and then it would need to very flat terrain to be of any use. I would have probably persevered and worked out a compromise set up by playing with gearbox internals and sprocket sizes but unfortunately medical problem intervened and stopped my bike riding.

[Rob]

It all seems to depend on the trial. I find that the Sidcup's Timber Woods LDT has some quite naggery sections and last time, due to bad weather and mud, were quite difficult. A lot of the trail bikes were running knobblies so they were reasonably OK. However, the Whitley 100 seems more set up for trail bikes and the sections are pretty straightforward and will pull a higher gear. I found much the same with the sections I saw on the Reigate, Redhill and North Downs LDT last weekend. The sections were mostly straight lines down and up and through gaps, etc. and the trail bikes made short work of them.

My one day event gearing is higer than a lot of people seem to run. I have a standard 20T engine sprocket with 13T gearbox and 60T rear wheel. For LDT's, I change the rear wheel to a 56T simply because I happen to have one. The gearing is still too low for the road work and I think I could up it for the Whitley and RRND trials.

We need 6 speed gearboxes as on my Yam trail bike which is fine on the road and low enough for sections. Nova Transmissions are about a mile away from me here so perhaps they will make me one for a couple of quid (or maybe not ...... !)

[ian640]

you need to maintain a low enough bottom gear to do the sections, whilst keeping a high top gear for the fast stuff.

That's the root of it. Maybe I'm pursuing the unachievable. All that said my last modern trials bike also didn't like roadwork.

It all seems to depend on the trial.
We need 6 speed gearboxes as on my Yam trail bike which is fine on the road and low enough for sections. Nova Transmissions are about a mile away from me here so perhaps they will make me one for a couple of quid (or maybe not ...... !)

I'll try some experimentation.

I had a quick look at Nova Transmissions web site. Has anyone ever crammed an extra gear or two into a Greeves?

[ian640]

I would have probably persevered and worked out a compromise set up by playing with gearbox internals and sprocket sizes but unfortunately medical problem intervened and stopped my bike riding.

As above some experimentation is called for.

Sorry to hear you're not riding and I hope you can ride again some day.