Boardtracker saga part 1:https://old.reddit.com/r/motorcycles/comments/cyhyde/boardtrack_bikes_history_and_notes_on_building_a/Part 2:https://old.reddit.com/r/motorcycles/comments/d1kfpn/boardtracker_build_concept_part_two_history_and/One of the first bikes that really caught my eye showing that a modernized boardtracker is possible at all is the "ABC 500" bike, likely the most exotic "boardtracker" ever made. Built by professional car designer Niki Smart, it's...well, glorious for a start, and appears to be part of his resume. Literally - his website on the bike also contains his actual resume :).https://www.abikecompany.com/abc500If you look at his design notes, it appears the first part he decided on was the tires - Vee, specializing in high end Harley stuff, came out with 120/50-26 rubber (!). Everything else followed in glorious metalwork and gobs of carbon fiber.His design notes:https://www.abikecompany.com/designHe's running front and rear suspension. The rear air ride shock is hidden under the seat and is pretty minimal. That plus the tire shape meant he had to make the seat fairly springy for a bit of extra comfort.One of the best things he's done is to use the engine as a stressed member, a trick the actual boardtrack racers didn't yet know about. Between that and the carbon fiber gas tanks (!) providing some horizontal support, this thing likely has a lot more resistance to horizontal flex than a vintage boardtracker.If want more on this bike:https://youtu.be/o-KGnUIDwAQHowever, I think he's made one key mistake. His choice of tire size and shape.If he leans too far into a corner everything comes unglued as he would be riding a 2mm-at-best edge of the rubber. This tire wasn't meant for lean angles. It was meant to be the front tire on a lowered Harley bagger show bike. It's awesome for straight line braking but cornering?Hell to the no.Ok. Next, what's he really getting? According to the tire size calculator here, just under 31" of outside diameter:https://www.rbracing-rsr.com/tirediamcalc.htmlSo what are the options?The tire shapes available in 23" rims suck just as bad. For 120/55-23 your outside diameter is a hair over 28", for 120/50-23 a hair under 28. And these sizes need 3" or more rim width. The only lightweight rims available are carbon fiber for, you guessed it, big bucks Harleys, so you're also limited to those axle and brake parts.Plus the rims are $2k each. Owwww.Coker Tires has "reproduction vintage" tires in various balloon shape (90/90-26 and such) but they can't be used on 3" wide rims plus they generally suck ass as far as real cornering goes. The only rims available for that rubber are steel hoop over spoke.Is there an answer? YES. Bigtime. And this guy found it - as did I before I saw this bike, but this guy's build shows me the answer is correct:https://motorbicycling.com/threads/excelsior-v-twin-build.39614/page-33That is a long build thread but let's cut to the chase:https://motorbicycling.com/attachments/m_img_3841-jpg.72940/https://motorbicycling.com/attachments/m_img_4151-jpg.72939/What he's done here is a low-bucks reasonably authentic reproduction of an Excelsior 1919 racer. He's close enough that at first glance, take it back to a track in 1919 and it won't look too out of place! Yeah, the motor is too small and the brakes would get a second look, and once they figured out it has a 5sp gearbox the game would be up :). But for a low-buck quasi replica this is a very legit bike.His tire size is 90/90-21. Yeah. You'd think that would be too small and it's not totally authentic, but his outside diameter is just under 28". These tires look right in terms of their profile, and they'll hang a corner! He's using Dunlops I think; Avon has the AM26 Roadrider in this size which I suspect is better. Good street rubber with strong cornering exists in this size because a lot of people are doing SuperMoto bikes with the stock 21" front rim, so they need a street cornering tire to fit that.Better yet, it's not listed online but Buchanan Spokes has 21" aluminum hoops that are 2.15" wide, perfect for that rubber. Assemble those on the hubs of your choice and you have a light, reasonably cheap setup.He's used bicycle frame parts adapted to take a Virago 250 motor, which is probably packing about as much power as a 1919 V-twin literbike :).Being in Australia he cannot street register this critter, sad to say, so he's kept it in race trim. One modernization I approve of: engine is a stressed member again, which is going to improve his horizonal stiffness over an original at least some, assuming the same basic frame quality. (Which isn't a given - a 1919 bicycle frame was stout as hell, maybe better quality than what our Aussie buddy had available as a starting point.)But he's proven to me that the boardtracker look is possible with good high performance rubber on reasonably priced lightweight rims.If Niki Smart had gone with 21" rims and this rubber, we could maybe have found out if Supermoto-grade lean angles were possible in something that looks like a boardtracker. But even then his minimal rear suspension would have hurt that effort :).In part 4 I'll show you what I have planned. I now have all the basic pieces available to build a bike that's recognizably descended from a boardtracker, has boardtracker in its lineage but shows what boardtrackers could possibly have become if modern tech had been thrown at them :).Complete with really fucking scary lean angles if I do it right :). via /r/CafeRacers https://www.reddit.com/r/CafeRacers/comments/da0d31/boardtracker_saga_part_three_a_look_at_two/?utm_source=ifttt
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