frankieboy Posted August 12, 2009 Report Share Posted August 12, 2009 (edited) Hi I am new to the site & to trials too, though have built from scratch many British Frame based specials over the years. I have a couple of old Bantams, one based on a 69/70 B175 Bushman,which has been Trialled for 2 or 3 years, t'other is a D10 engined D7 & its gonna be a Trials style road runabout! I have a friend who is going to rebuild the Wheels for me shortly, & for the rear I wondered if anyone could advise what offset from central to have the rear wheels laced. I have 4.00 x 18" rear Trials Tyres, & was intending to use WM3 Rims, though it has been said that WM2 Rims should be used? I have some thicker rear engine plates from Rex Caunt Racing, in case I have to move the Engine over to the left, but would prefer to avoid this if possible.The swinging arm has been widened by the previous Trials owner, too. But I bought the Bike as a bare Frame Forks & swinging Arm, & have built it up from there. currently there isnt an Engine for it, but will hopefully be getting a B175 or D14/4 for it in due course. The Forks for the Bushman Trials are from an early Honda SL/XL/TL ? 125 which I have fitted a TY175 front Wheel in. The Roadgoing/Trials runabout, is a 62 D7 fitted with a D10 Engine, & I have so far fitted a C15 set of Forks to it. I intend fitting a WM1 x 21" front alloy rim laced to the Bantam Hub & a WM3 x 18" rear alloy rim laced again to the Bantam Hub, (but am wondering whether WM2 should be used??) The engine I have in this is a standard 3 speed D10, which I shall use initially, then change for a 4 speed engine in due course. I shall Probably fit this one with Bushman Trail gearing & a decent carrying rack on it too. Any advice/help/ideas from you trials experts would be much appreciated, many thanks, all the best Frankieboy Edited August 14, 2009 by Frankieboy Quote Link to comment Share on other sites More sharing options...
alan_nc Posted August 12, 2009 Report Share Posted August 12, 2009 Frankie, If you are going to use a "real" Trials tire you will need to go to a Cub swingarm. They give you about 7/8" more room. It's a direct bolt on, no cutting or grinding - just push the pin out and put the new one in place. Once I had gone to the Cub swingarm I went ahead and used the Cub rear wheel/hub/brake. It isn't a problem lining it up but I sure can't tell you what the exact offset is. Alan Quote Link to comment Share on other sites More sharing options...
frankieboy Posted August 13, 2009 Author Report Share Posted August 13, 2009 (edited) Hi Alan, many thanks for that! well the Swinging Arm has already been widened to Cub spec by the previous owner who used it for Trials for 2 or 3 years, with a proper trials tyre 4.00 x 18" I have a 4.00 x 18" Proper Trials IRC tyre which I am using. I'm hoping not to have to move the engine over, (when I get one!!!) thats why I want to know the offset of the Hub in the Rim! so I can have the wheels built up. also whether I NEED to use a wm3 size Rim, or whether a wm2 would be better? best regards Frankieboy Edited August 13, 2009 by Frankieboy Quote Link to comment Share on other sites More sharing options...
alan_nc Posted August 13, 2009 Report Share Posted August 13, 2009 Frankie, I did not have to move the engine to line things up. I am using a stock rim from a '66 Cub (don't know which wm that is). Someone else may know the answer to this: Will the 18x4 tyre fit on both style of rim? I thought the 4" dimension was to wide for one of them. The real problem I had (still have) is foot peg position and mounting. I use the bracket for mounting rear pegs and have re-drilled it for my 'rider' pegs. I have cut and re-welded the rear portion of the frame (under the seat) so that you can stand on the bike without standing bow-legged. The bike I use is a numbers matching '59, but I have mounted a '65 gas tank as they are much narrower. They really are fun to ride. As far as we can tell there are only 2 of us in the USA that compete/have competed on Bantams. Alan Quote Link to comment Share on other sites More sharing options...
frankieboy Posted August 13, 2009 Author Report Share Posted August 13, 2009 (edited) Alan, well the 66 cub standard wheel rim I should think is a wm2 x 18" but they varied depending on which year & model cub it came from.If you let me know, I can check it out in The Tiger Cub Bible which I have a copy of & its stacked with all the specs of all the years & variations, but if the rim is an original, it will have it stamped on it ie: wm2 x 18" or wm3 x 18", most replacement rims of 40 spokes will be stamped with their size.The modern & japanese rims are measured & stamped differently & I think this is how they compare ie: 1.65 equiv to wm1, 1.85 equiv to wm2, 2.15 equiv to wm3 & so on. I just sold an old Cub Rim with the cast iron Hub,that was a front & it was a wm2 x 17" I know what you mean re footpeg position, cos the way mine was set up, the seat seemed far too low in relation to the position of the Bars/Pegs, but from pics all the pre65 Trials Bikes now seem to have the set up much the same, I have a lowered subframe on mine, & have put some risers on it for the seat, but may remove them once I get it to a rideable stage, I'll have to see how it goes. I'm 5' 11" same height as the guy who altered it & Trialled it, but it sure doesnt suit me, but we'll see! also. are you running a 4.00 tyre in yours? Frankie Edited August 14, 2009 by Frankieboy Quote Link to comment Share on other sites More sharing options...
alan_nc Posted August 13, 2009 Report Share Posted August 13, 2009 Frankie, The wheel I'm using is a WM2x18 and it will fit a 4"x18" with no problem. I'm using an 80 tooth rear sprocket and a 14 tooth front (would go to 13 if I could find one). Pulls O.K., but runs out of steam if it's a long hill. I'm running the standard 3 speed trans, never use anything but 1st in sections. Let me know if I can help with any questions. Alan Quote Link to comment Share on other sites More sharing options...
frankieboy Posted August 14, 2009 Author Report Share Posted August 14, 2009 (edited) Alan Ha Haaaaaaaaaaaa Brilliant, I'd seen that Photo when Trawling around a couple of weeks back, didnt realise that was you, nice to put a face to ya mate! Blimey thats the biggest rear sprocket Ive seen on a Bantam! Over here, they change the front engine (crank) sprocket for a smaller one too, as well as using a small gearbox sprocket, enables you to still get a very low ratio without having to use such a large rear one. all sizes of gearbox sprockets are available over here dependent on your chain size, let me know what yours is & I'll see if I can direct you where to get one, all advertised on ebay by Trials parts suppliers in the UK. I havnt sorted posting photos on here yet, will probably subscribe, shortly & do it that way. meanwhile, if you send me ur email I'll send some pics of my projects. I have same bars & similar (Bushman Tank) on mine, but I wanna change the Bars or the top yoke, to get them further forward too & maybe an alloy Tank later too. Youd think that you were in the UK by the pic. Nice one Frankie Edited August 14, 2009 by Frankieboy Quote Link to comment Share on other sites More sharing options...
frankieboy Posted August 14, 2009 Author Report Share Posted August 14, 2009 (edited) Alan Try these: NSA Classic Motorcycles spares in suffolk england, (ebay seller: njavery) they have a 13t sprocket at Edited August 14, 2009 by Frankieboy Quote Link to comment Share on other sites More sharing options...
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