Guest majestyman340 Posted March 7, 2008 Report Share Posted March 7, 2008 majestyman340, that's one of those "it depends" situations. Do you need a faux-replica of a modern bike in order to clean your twinshock sections or Pre65 sections? Is the steering geometry on a modern bike the determining factor, or does 40-50lbf less weight play a part?"Ideal" rake seems to steepen as the years go past. Tony Foale has done some experiments showing that you need some trail, but bikes with zero rake (this was his R75 BMW being used as a test bed) were quite rideable, and it appears that getting rake down into the 10-15 degree range can have some benefits. You can see an article about that at http://www.tonyfoale.com/Articles/RakeEx/RakeEx.htm But with a bike with a regular steering head it gets really awkward to get the steering head attached in a position to allow those steep rakes.and there are photos in the article that show how far the steering head has to move forward. Also note that Tony comments that with steeper rake the bike is less sensitive when dealing with ruts, and that may be a definite factor in steeper rakes for trials bikes. Are 2-3 degrees less rake going to make you suddenly clean every section you ride? I wouldn't expect that if I were the rider. I think that getting enough practice and skill so that we can ensure the wheels are exactly where we want them in a section, instead of just within +/- 12", is far more likely to improve our scores than changing from steering geometry that has proven to be "good enough" for many people. If you are converting some bike that originally came with 32 degrees and 5" of trail into a trials bike, then I'd think that yes, deraking it down into the 26-27 degree range is probably going to be a good move. If you are starting with something that was pretty well designed to be a trials bike you are probably going to start seeing a case of diminishing returns. What I am trying to say that if you make a change to one thing a person needs to consider all the possible ramifications and then decide if they also need to be addressed at the same time. If you change the rake you've now got a different trail number if you didn't change clamps. If you moved the front wheel around while changing rake (or changing the clamps) you now have a different wheelbase and weight distribution. Does changing just the rake and letting all the other factors end up where ever they happen to end up make things better? Beats me. Like Dirty Harry said in the movie, you've got to ask yourself "do you feel lucky?" When I build a new frame for my KT250 or my TTY400 projects I'll probably just use 26-27 degrees as the different forks I've got were all designed with offsets for that kind of rake, and I won't have to (at least at the start) have to make new triple clamps too. And for a pre 1978 class bike (AHRMA Modern Classic) the front end of the bike will look period with that kind of fork rake, where if it had 21 degrees it wouldn't. I'd find it interesting to do some experimentation to try and determine what changes do have a significant effect, and whether that effect is good or bad, and how that change interacts with other changes. Footpeg and handlebar positions seem to have noticeable effects without changing the frame around. Engine position (up/down, fore/aft) can have an effect without changing steering geometry. Mix four or five things up and who knows where you'll be, or if you'll be able to say "oh, it was obviously the steering rake change that made the bike better, and the changes to foot pegs and wheelbase and engine location had no effect." But I'd do that kind of experimentation for the fun of it, not because I expect it will make me an expert trials rider. It may be that the experimentation would lead to some conclusions like "the footpegs are better off at the leading edge of the rear tire and 12" off the ground instead of 3" behind that point and 3" higher" and I could modify my bike accordingly and make some small changes where the original designers don't seem to have gotten things right. I'd be loathe to make any blanket recommendations like "every trials bike in the world should be modified to have 22.5 degrees of rake, and you should sacrifice any other dimension needed to arrive at that rake angle." Don't forget too that different people like different things. Some people love to slide a MX bike around a course and go just as fast as someone who loves to square off every corner. Figuring out what YOU are comfortable riding and what works with YOUR riding style is important. Paioli, trial and error can definitely get you there. But knowing what counts as "error" so you can avoid trying it is likely to get you there quicker. cheers, Michael Mike quite simply I would like my original Godden framed Majesty to handle a bit better.....................what angle do you set the head angle on the trials chassis you manufacture, and is this any different to any stock chassis that you modify? Quote Link to comment Share on other sites More sharing options...
paioli Posted March 7, 2008 Report Share Posted March 7, 2008 same guy who built Chris Koch's twin shock legal bike , still interested ! ty mono forks seem to be the safe bet from the owners who have fitted them ! Still no concrete ideas on any twin shock guidelines/rules ! how about pre75 original pre85 original twin shock evo e.g. new frame kits/mono sourced parts/one off specials with air-cooled motor and drum brakes ! original class means just that , how it left the factory to exclude , cables, handlebars/controls, electrical systems, tyres and rims! Anyone else got any idea's ! Quote Link to comment Share on other sites More sharing options...
paioli Posted March 7, 2008 Report Share Posted March 7, 2008 Forgot to put in oridginal class ,yokes and forks must be fitted ! Early days ! Quote Link to comment Share on other sites More sharing options...
Guest majestyman340 Posted March 7, 2008 Report Share Posted March 7, 2008 same guy who built Chris Koch's twin shock legal bike , still interested ! ty mono forks seem to be the safe bet from the owners who have fitted them ! Still no concrete ideas on any twin shock guidelines/rules ! how about pre75 original pre85 original twin shock evo e.g. new frame kits/mono sourced parts/one off specials with air-cooled motor and drum brakes ! original class means just that , how it left the factory to exclude , cables, handlebars/controls, electrical systems, tyres and rims! Anyone else got any idea's ! Thats just the type of rules that are needed to prevent twinshock being ruined in the same way as P65.............very good suggestions. Dont agree at all with modified mono bikes in the twinshock class, but am very interested in having my Majesty properly modified in a jig, so would be very helpful if you can pm me contact details of guy that built Chris Koch bike. Quote Link to comment Share on other sites More sharing options...
michaelmoore Posted March 7, 2008 Report Share Posted March 7, 2008 what angle do you set the head angle on the trials chassis you manufacture, and is this any different to any stock chassis that you modify? I haven't done a trials bike yet. I've built or modified several RR frames and a couple of vintage scramblers. I think I mentioned above that on the trials frame I'll probably just use 26/27 degrees as that should work OK with the KT250 or Bultaco fork sets I've got on hand. Modern rake angles wouldn't look period and if I'm going to ride a vintage bike I want it to look period.. On my KT250 I'm not concerned particularly about turning it into a worldbeater and I may just jig off the stock frame for steering head/swing arm pivot/damper mount positions. Mostly it is that the way they built the stock frame and swing arm annoys me every time I look at it. I can't imagine why they built it like that when they could have copied a Rickman, Cheney, Gollner or other frame design of the period (or evey 5-10 years earlier) instead of making it look like some late 1950s frame. cheers, Michael Quote Link to comment Share on other sites More sharing options...
frenchie Posted March 7, 2008 Report Share Posted March 7, 2008 I am struggling to understand why you are so adamant that Majesty's should be classed in I assume your evo class, if they have mono yamaha forks and unable to compete in the Pre 85 class. Are these forks any different, do they provide any advantage and do they look any less period , certainly if like mine have had the paint removed and polished than say Fantic, SWM late montesa and of course Honda's. I would be interested if others agree with you and if so, is it because of any advantage gained ie. Its cheating, or they prefer just to see bikes in their original state as they left the factory. Bonsoir et bon weekend. Quote Link to comment Share on other sites More sharing options...
Guest majestyman340 Posted March 7, 2008 Report Share Posted March 7, 2008 I am struggling to understand why you are so adamant that Majesty's should be classed in I assume your evo class, if they have mono yamaha forks and unable to compete in the Pre 85 class. Are these forks any different, do they provide any advantage and do they look any less period , certainly if like mine have had the paint removed and polished than say Fantic, SWM late montesa and of course Honda's. I would be interested if others agree with you and if so, is it because of any advantage gained ie. Its cheating, or they prefer just to see bikes in their original state as they left the factory.Bonsoir et bon weekend. The step from Yam mono forks to Gas Gas or Beta may well be pretty wide, but like it or not they are not what was fitted to the bikes orginally, and to prevent twinshock suffering the same fate as P65 some sensible rules are needed. Anyone with mono forks fitted that doesnt want to ride in the evo class, can simply refit their original forks. Quote Link to comment Share on other sites More sharing options...
pitley Posted March 7, 2008 Report Share Posted March 7, 2008 (edited) I couldnt give a toss what forks folk are using as long as the sections are set out properly EG no stupid tight turns and mental drop offs! Reason i use mono forks in my maj is the standard forks were rusty as a horseshoe and they were crap Yes aggred the rules should be set in stone for any National series that have twinshock classes about machine eligabilty. At the end of the day its the rider with the best skill and ability that wins the trial, not the bloke with the most tricked up frame and forks! Lets just enjoy our sport while we still can! Edited March 15, 2008 by pitley Quote Link to comment Share on other sites More sharing options...
majesty320 Posted March 7, 2008 Report Share Posted March 7, 2008 Why would you want to alter the steering angle on a Godden Majesty to a more modern setup. This would make the bike even shorter and thats the last thing you want especially with standard forks, as its twitch enough already. If you want a bike with modern steering geometry buy GasGas, beta, mont etc not a twinshock Quote Link to comment Share on other sites More sharing options...
woody Posted March 8, 2008 Report Share Posted March 8, 2008 Why would you want to alter the steering angle on a Godden Majesty to a more modern setup. This would make the bike even shorter and thats the last thing you want especially with standard forks, as its twitch enough already. If you want a bike with modern steering geometry buy GasGas, beta, mont etc not a twinshock Yes, I'm with you and have already said as much. I had the head angle altered on my Majesty but it's back to (hopefully) somewhere near normal again now. I'm also well past giving a flying f*ck what people do to their bikes. I'm only interested in enjoying getting out and riding my bikes. If there are no twinshock events on at a weekend I'll ride them on the middle route at modern events and have no interest in whether there is a twinshock class to enter against or not. I steered my Ossa MAR round every section in last week's modern trial without using the clutch on one single turn. It has the original steering angle and coped fine. As long as there is a route that the bike and me can cope with that provides a good challenge that's good enough - ie; yellow route at South Shrops or Llanfyllin events It's a pity we can't have a national twinshock championship like the Spanish series. Paioli's starting point is a good basis, but even if we had rules established. riders would still break them, no-one would try and enforce them and how many people would actually know what to look for anyway. How many organisers would know the difference between say a 76, 77 or 78 Sherpa and be able to spot any parts that shouldn't be there in a Pre77 class. Agreement would never be reached on rules anyway. Personally I don't think lightweight replica frames should be allowed but equually I couldn't really care if someone has one. The new Majesty frames are a difficult one as it is only reintroducing a frame kit that was available at the time. Could be argued I guess that it could have been made to weigh the same as the original as a true copy. Others will think that a replica lightweight frame is ok whereas some don't think Yam mono forks should be fitted. I've lost count of the number of times I've said that mono forks are only on a par with the last Marzocchis to be used on 240 Fantics and the like. If I'd had a pair of Marzocchis I'd have fitted them to my Majesty to replace the sh*te originals. I didn't, but I did have an old knackered mono which provided it's forks for nothing. Fitting GasGas or suchlike forks is going too far but again, couldn't give a stuff anymore if someone does it. This weekend I will be mostly riding my 1968 Sherpa complete with chopper head angle and thoroughly enjoying riding it too - providing it doesn't break down, first time out on the road on it. Ah, but it will have modern footrests fitted so I've entered the specials class.. Quote Link to comment Share on other sites More sharing options...
Guest majestyman340 Posted March 8, 2008 Report Share Posted March 8, 2008 Why would you want to alter the steering angle on a Godden Majesty to a more modern setup. This would make the bike even shorter and thats the last thing you want especially with standard forks, as its twitch enough already. If you want a bike with modern steering geometry buy GasGas, beta, mont etc not a twinshock I am looking for the same steering geometry as the Trevor Kemp has on his special one off Majesty frame, which I understand was made by a company that also makes moto gp frame kits..................... Quote Link to comment Share on other sites More sharing options...
Guest majestyman340 Posted March 8, 2008 Report Share Posted March 8, 2008 It's a pity we can't have a national twinshock championship like the Spanish series. Paioli's starting point is a good basis, but even if we had rules established. riders would still break them, no-one would try and enforce them and how many people would actually know what to look for anyway. How many organisers would know the difference between say a 76, 77 or 78 Sherpa and be able to spot any parts that shouldn't be there in a Pre77 class. Sadly as the uk twinshock championship now caters mainly for older guys riding modern bikes, a proper classic series such as there is in Spain just isnt going to be possible. As for a set of rules that might prevent t/s being ruined in the same way as p65, it looks like they have got it right in Spain, so why not something along similiar lines here? Quote Link to comment Share on other sites More sharing options...
Guest majestyman340 Posted March 8, 2008 Report Share Posted March 8, 2008 Grinder+brickwall+home made guage+mig= better stearing, works every time for me ! no x=y-x+$ to the power of 6 just a bit of trial and error and picking the brains of a bloke whose been building twinshocks for the last 40 years ! Spoke to guy that built Trevor Kemp's ultra trick Majesty chassis yesterday, and asked about altering head angles. He was horrified when I asked if it was possible to do the job in the way suggested above......... apparently this can result in bent forks, distorted sliders, and possible distortion of the head stock itself, which will cause a tight spot in the steering. Sadly he wasnt interested in altering my bike properly, so I hope the chassis builder in Cheltenham I have been told about will be able to do it for me! Quote Link to comment Share on other sites More sharing options...
tony283 Posted March 8, 2008 Report Share Posted March 8, 2008 majestyman340, I'll post a few shots of Trevors's frame and final build tomorrow. Tony Quote Link to comment Share on other sites More sharing options...
pitley Posted March 8, 2008 Report Share Posted March 8, 2008 Last time i saw a picture of Trevor Kemps Majesty it had mono forks fitted............................. Funny old life init... Quote Link to comment Share on other sites More sharing options...
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