feetupfun Posted March 30, 2011 Report Share Posted March 30, 2011 I believe I know what you are talking about, and the fork tube "rake" is controlled by the triple-clamps/steering stem. No production twinshock trials bike that I am aware of has an adjustsble steering stem so the triple-clamp rake angle is held constant. Some KTM models have an adjustable 2 degree offset steering stem, but the rake is held constant. It's quite possible that one manufacturer or more has in the past built a trials bike with a "raked" triple-clamp but I have been a motorcycle mechanic for over 35 years and have owned two bike shops, one currently, and I have never seen one nor have seen in a service manual that dimension being called out. I am in the process now of designing my own twinshock chassis's, and have a fairly large database of chassis geometry numbers, so if you know of a particular trials bike that has a "raked" triple clamp I It is bedtime now but I will endeavour to take some photos tomorrow evening Quote Link to comment Share on other sites More sharing options...
mrb505 Posted March 30, 2011 Report Share Posted March 30, 2011 (edited) I had always thought the steering head was parallel to the fork tubes but then I checked by sight, getting down on my haunchs one eye closed line the top of the fork tube to the steering head so they are just touching then look down to the lower end of the steering head there is a definite gap at the bottom looks to be roughly 2mm ,its basically using the same principle of using a plumbob, if someone held a ruler whilst your sighting you'd probably get a fairly precise measurement. I tried this on a TYmono , TLR200 and a M125 Sherpa my M49 is pulled apart at the moment but I'll have a look when its back together, both the Jap bikes seemed to have a bit less than the Sherpa the TLR seems to have the smallest gap. Ross Edited March 30, 2011 by mrb505 Quote Link to comment Share on other sites More sharing options...
jc2 Posted March 30, 2011 Author Report Share Posted March 30, 2011 I believe I know what you are talking about, and the fork tube "rake" is controlled by the triple-clamps/steering stem. No production twinshock trials bike that I am aware of has an adjustable steering stem so the triple-clamp rake angle is held constant. Some KTM models have an adjustable 2 degree offset steering stem, but the rake is held constant. It's quite possible that one manufacturer or more has in the past built a trials bike with a "raked" triple-clamp but I have been a motorcycle mechanic for over 35 years and have owned two bike shops, one currently, and I have never seen one nor have seen in a service manual that dimension being called out. I am in the process now of designing my own twinshock chassis's, and have a fairly large database of chassis geometry numbers, so if you know of a particular trials bike that has a "raked" triple clamp I would be very interested in seeing the numbers. JMcK, I don't know what you are looking at. We are not talking about adjustable triples. We're talking about triples where the bottom one has more offset than the top one so the forktubes are kicked out about 1.5deg more than the steering stem. Most 70s twinshock trials bikes had it, including the TYs & SherpaTs. Quote Link to comment Share on other sites More sharing options...
feetupfun Posted March 31, 2011 Report Share Posted March 31, 2011 (edited) Photos of TY175, TY250 and KT250 illustrating fork tube angular offset http://www.trials.com.au/content/index.php?option=com_wrapper&view=wrapper&Itemid=42 In case that link does not work for you, the posting is in the Technical Help forum of trials.com.au Edited March 31, 2011 by feetupfun Quote Link to comment Share on other sites More sharing options...
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