See my other posts for details on the project. My donor bike was a 1993 Suzuki GSXR 750. It had 120/70 17 on the front and 160/70 17 on the rear. What are your thoughts on sticking with 17's. I have aluminum hubs in hand, and am sourcing rims and spokes. I was going to go wit a 18 3.50 in the rear and 18 2.50 on the front. But I think the 17's would be good, and I wouldn't have to modify the front fender mount. Thoughts? I'll await hobot's response.
Selecting project tire size
- Thread starter bwolfie
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hobot response,
if you seek land speeds over 200 mph, for long, you need 17" Z+ rated tires.
If you seek sexy fat meat look then you need 17" rims for wide squat tires.
If you seek step through scooter handling you need 17 to 16"or less wheels.
If you seek similar effort and delay as sports moderns you need 17" rubber.
If you can still put a knee out in best leans you can get away fine on 17" size.
If you use rear tires up under 3000 miles in normal use, fit 17" 'spent' $50 race tires.
If you don't intend off pavement adventures stick with 17" current issue.
I hobot can offer no further reasons to recommend 17" modern tires.
if you seek land speeds over 200 mph, for long, you need 17" Z+ rated tires.
If you seek sexy fat meat look then you need 17" rims for wide squat tires.
If you seek step through scooter handling you need 17 to 16"or less wheels.
If you seek similar effort and delay as sports moderns you need 17" rubber.
If you can still put a knee out in best leans you can get away fine on 17" size.
If you use rear tires up under 3000 miles in normal use, fit 17" 'spent' $50 race tires.
If you don't intend off pavement adventures stick with 17" current issue.
I hobot can offer no further reasons to recommend 17" modern tires.
Hi,
Spacing may be a problem for you with stock drive and swingarm (that is if you are trying for any tire width gain). I believe the modern Nortons (IE 961) are fitted with 17 inch rubber. They also have right hand drive which effectively handles any spacing problem.
GB
Spacing may be a problem for you with stock drive and swingarm (that is if you are trying for any tire width gain). I believe the modern Nortons (IE 961) are fitted with 17 inch rubber. They also have right hand drive which effectively handles any spacing problem.
GB
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I fear for you and your bike reputation and intact-ness if retaining isolastics w/o Patton's rear link or Ms Peel's triple rod Watt's like linkage. You will be better off to solid mount engine, rise crank mass to 80's BF to stay within limits of 17" fatsos. An isolastic Commando gets real dangerous real quick trying to play real games with real sports riders or supermotards. If just playing with your self, no ego to win or lose, just sane joy rides, continue on current path and concepts.
Only reason to modify a great design is to show off, test your skills or perform better. Serious question for serious efforts.
I'm not speculating, I know what its like to hang with hi hp bikes/riders in close tights and then try to follow them into sweepers on two factory isolastic Combats with plenty of power left to keep up with them speed acceleration wise over 80 mph while leaned real good for over a couple of seconds. Only
time I run into traction limits of skinny tyres on Combats is braking or skiing THE Gravel. The handling decays before tire grip on highway pavement.
First few times were pure accidents I had to save desperately, last times on Trixie Combat was merely to assure myself its an innate down fall and learn definitively its onset riding into and out of "IT" to KNOW TO AVOID NEVER EVER TO DO IT AGAIN. Its exactly the same to ride out a blow out on either end.
asmhik.
Only one I know that is competitive with similar craft on isolastic Commando is racer Dough McRae. He must have steel balls and tight isolastics as he and frame endure some obnoxious level of vibration. In the end I don't see him staying on power into turns anymore than solid chassis vintage or moderns. Supermotards generally don't have the power to spin tyre to 'back' into sharps, they mainly use rear brake, HA! A torquey hot rod Cdo can if willing to rev engine well leaned.
I've pressed my life on 19-18" narrow tires and on best there is on a bunch of brands of non DOT 17" race tires. Fat tire patch profile distorts and shortens up its edges to side loads a lot faster worser than longer foot print of 19-18" near profile limits.
If bike/rider in similar weight range the actual patch area of 17 to 19-18" is almost identical, so mainly its compound then profile that matter most. IF all's ya bike can handle much is shallow leans and straight line sprints, fatter tires are better and allows more hook up sooner - Coming Out of Apexes once more upright. pashaw.
Until I tasted rear linked isolastic Command on skinny tires I too thought like the rest of the world, now i know elites ain't hardly getting up to low orbit before they fall back down. I'm also spoiled now by the light effort to maneuver 'skinny' tires over fatso. I know that steering dampers can slightly extend the handling upset of Commando or moderns but then interferes with front tire road following changes and completely with fast recover of crisis.
On isolastic Cdo fat tires will just make more sluggish all around and not give any corner advantage. Your chain run limits width. About 1/4" can be gained moving gear box sprocket outward and another ~3/8" centering rim or moving it to RH off center some. Handling effects are undetectable moving rear out of line with front by this amount. Another important factor is to compare tyre+wheel mass.
I'm spending a whole bunch to wipe the socks off anything but 4wd drive rally cars, you know my tool of [proven] choice now. Biggest danger on Ms Peel is she don't have to slow down for anything but hazards in lane, going beyond race bike speed through tight chicanes or long sweepers is boring mundane, I don't get orgasm G's going till she turns em all into harsh accelerating fast decreasing radius wonders. I have yet to try Peel with full street tires let alone real race rubber. Let that sink in narrow or fatso. I think of fat squat tires as greasers, narrow as slicers.
Only reason to modify a great design is to show off, test your skills or perform better. Serious question for serious efforts.
I'm not speculating, I know what its like to hang with hi hp bikes/riders in close tights and then try to follow them into sweepers on two factory isolastic Combats with plenty of power left to keep up with them speed acceleration wise over 80 mph while leaned real good for over a couple of seconds. Only
time I run into traction limits of skinny tyres on Combats is braking or skiing THE Gravel. The handling decays before tire grip on highway pavement.
First few times were pure accidents I had to save desperately, last times on Trixie Combat was merely to assure myself its an innate down fall and learn definitively its onset riding into and out of "IT" to KNOW TO AVOID NEVER EVER TO DO IT AGAIN. Its exactly the same to ride out a blow out on either end.
asmhik.
Only one I know that is competitive with similar craft on isolastic Commando is racer Dough McRae. He must have steel balls and tight isolastics as he and frame endure some obnoxious level of vibration. In the end I don't see him staying on power into turns anymore than solid chassis vintage or moderns. Supermotards generally don't have the power to spin tyre to 'back' into sharps, they mainly use rear brake, HA! A torquey hot rod Cdo can if willing to rev engine well leaned.
I've pressed my life on 19-18" narrow tires and on best there is on a bunch of brands of non DOT 17" race tires. Fat tire patch profile distorts and shortens up its edges to side loads a lot faster worser than longer foot print of 19-18" near profile limits.
If bike/rider in similar weight range the actual patch area of 17 to 19-18" is almost identical, so mainly its compound then profile that matter most. IF all's ya bike can handle much is shallow leans and straight line sprints, fatter tires are better and allows more hook up sooner - Coming Out of Apexes once more upright. pashaw.
Until I tasted rear linked isolastic Command on skinny tires I too thought like the rest of the world, now i know elites ain't hardly getting up to low orbit before they fall back down. I'm also spoiled now by the light effort to maneuver 'skinny' tires over fatso. I know that steering dampers can slightly extend the handling upset of Commando or moderns but then interferes with front tire road following changes and completely with fast recover of crisis.
On isolastic Cdo fat tires will just make more sluggish all around and not give any corner advantage. Your chain run limits width. About 1/4" can be gained moving gear box sprocket outward and another ~3/8" centering rim or moving it to RH off center some. Handling effects are undetectable moving rear out of line with front by this amount. Another important factor is to compare tyre+wheel mass.
I'm spending a whole bunch to wipe the socks off anything but 4wd drive rally cars, you know my tool of [proven] choice now. Biggest danger on Ms Peel is she don't have to slow down for anything but hazards in lane, going beyond race bike speed through tight chicanes or long sweepers is boring mundane, I don't get orgasm G's going till she turns em all into harsh accelerating fast decreasing radius wonders. I have yet to try Peel with full street tires let alone real race rubber. Let that sink in narrow or fatso. I think of fat squat tires as greasers, narrow as slicers.
Over the years, on this forum, I've read many testimonials as to the superior handling of tire size "X" vs. tire size "Y" and brand "X" vs. brand "Y". While I don't doubt the veracity of the writer's claims, I do conclude the claims are subjective. A more valid comparison would probably be a blind (not knowing which tire you are running) test on a track with timed results. I would venture to say there are very few bikers who even come close to using today's modern tire potential.
grandpaul
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JimC said:
The voice of reason speaks.
The same reply also fits many other subjects such as suspension and fine-tuned steady rigging tweaks.
I'd venture a guess that less than 25% of the people on this forum (I am in the 75% group) can handle a Commando at it's absolute safe limits on a track (I mean without dumping it).
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I don't mean to hijack this thread, but my question is similar. I'm a new member to this forum, and haven't looked through the older posts, so excuse me if this has been covered before.
I have another set of hubs that I'm considering lacing up with stainless spokes and alloy shouldered rims. I like the looks of the high shoulder. I'm going to leave the front at 19", but am considering going to a slightly wider 18" rear, with the 4.25-18 K81 TT-100 tire. I'll lose about .5'" on the diameter.
Has anyone gone this route?
I have another set of hubs that I'm considering lacing up with stainless spokes and alloy shouldered rims. I like the looks of the high shoulder. I'm going to leave the front at 19", but am considering going to a slightly wider 18" rear, with the 4.25-18 K81 TT-100 tire. I'll lose about .5'" on the diameter.
Has anyone gone this route?
gnolan said:
Many have done it including myself, I had a WM3 X 19 on the front with a WM4 X 18 on the back. The front tire is a 90 x 90 x 19 and the back 4.25 x 18. Wider rims make the tire look a bit fatter and lower and works better with wider tires. I never liked the look of Commandos with a 4.10 tire on the front.
Jean
gnolan said:
I have a set of flanged for sale see this thread
lots-parts-and-front-and-rear-wheel-assemblies-t8114.html
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You all can speculative till the cows come home but I've tested tire grip on different surfaces rather faster than seen by racers whose career depends on going fast as they can. Nothing so far but maybe 4wd rally cars or race Karts can deliver-sustain the G's and grip of my Ms Peel with rod links on skinny 120 tire with chunks of profile missing. Also tested at further lean angles than racers can sustain and still keep tire on surface. When one runs a bike flat past both tires adhesion or contact a whole 'nother world of wildness hits.
Summary if ya stick with too rigid a chassis or too flexy a Commando then hardly matters what tire ya stick on. I fully intend to data log my findings in spades against most elite computer controlled cycles but I don't need none of that to know how hard I'm pressed into seat or wrists stained, nor how quick a turn is gone through to know what works best for me. I tease thee not to save riding past normal tire and chassis limits testing requires controlling low to hi side crashes. Fat tires get greasy too soon for me and make bike feel sluggish in response. If I relieve rear tire to stay in grip the front lets go, if I put more load to turn on front the rear can't take much power, ugh.
Fat wide tires are just for heat handling in mostly upright sprints, so helps some by less melting lost of traction. Mostly a wear factor than adhesion one. In tights that don't last but part of a second a factory Combat can lean on and hook up a 110/19" tire enough to sideways wheelie when rpms get above upper 6000's.
What I would 'fear' the most is a mono shock triple rod linked Commando on 120 or 130 18" rim rear. In my case I get going so fasting in such close turns that its impossible for human power/speed to change bike lean or fork aim fast enough to prevent flying right out at a tangent - so I learned to trip bike down by over powering rear at full lean to get the hi side back up in right new direction in time. You can't believe how crazy it is to do on fat tire moderns, but its a breeze on rear linked rubber baby buggy on narrow meat.
Fat tires can not take the loads of flipping into Straight Steering mid apex, they all have to back off or just fly wide and lazy - relieving acceleration like flat trackers all crossed up with a foot down becoming like a child's tricycle. I have nil respect for fatso tires nor traction control that limits tire spin when most needed to get excessive hook up out to there an instant latter.
[video]http://www.youtube.com/watch?v=PIjkkArG2TA&NR=1[/video]
Summary if ya stick with too rigid a chassis or too flexy a Commando then hardly matters what tire ya stick on. I fully intend to data log my findings in spades against most elite computer controlled cycles but I don't need none of that to know how hard I'm pressed into seat or wrists stained, nor how quick a turn is gone through to know what works best for me. I tease thee not to save riding past normal tire and chassis limits testing requires controlling low to hi side crashes. Fat tires get greasy too soon for me and make bike feel sluggish in response. If I relieve rear tire to stay in grip the front lets go, if I put more load to turn on front the rear can't take much power, ugh.
Fat wide tires are just for heat handling in mostly upright sprints, so helps some by less melting lost of traction. Mostly a wear factor than adhesion one. In tights that don't last but part of a second a factory Combat can lean on and hook up a 110/19" tire enough to sideways wheelie when rpms get above upper 6000's.
What I would 'fear' the most is a mono shock triple rod linked Commando on 120 or 130 18" rim rear. In my case I get going so fasting in such close turns that its impossible for human power/speed to change bike lean or fork aim fast enough to prevent flying right out at a tangent - so I learned to trip bike down by over powering rear at full lean to get the hi side back up in right new direction in time. You can't believe how crazy it is to do on fat tire moderns, but its a breeze on rear linked rubber baby buggy on narrow meat.
Fat tires can not take the loads of flipping into Straight Steering mid apex, they all have to back off or just fly wide and lazy - relieving acceleration like flat trackers all crossed up with a foot down becoming like a child's tricycle. I have nil respect for fatso tires nor traction control that limits tire spin when most needed to get excessive hook up out to there an instant latter.
[video]http://www.youtube.com/watch?v=PIjkkArG2TA&NR=1[/video]
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geo46er said:
He was going to use a modern swingarm, but he probably hasn't addressed how to offset the sprocket to clear a wider tire. Which is the actual challenge for adding a wider tire to a Norton (or most old British bikes for that matter).
swooshdave said:
I'm using a 1982 yamaha IT465 swingarm. Once I get it modified and mounted then I will look at moving/modifing the sprocket. I don't have the limitations of the primary cover, so that gives me a little room. Just the clutch to deal with..
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bwolfie said:
It's not the primary cover that you have to worry about. It will be interesting to see what you come up with.
swooshdave said:
I think the only way would be to replace the transmission with one from a
Harley in order to cross over the engine drive and the final drive. Most bikes now are built just like that in order to clear the wider tires. The only other option would be to add a jackshaft to move the chain line out, but then, what would break next :?: Unless going for looks alone, fatter tires are overkill on a Norton, not enough power.Jean
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bwolfie said:
It will be interesting to see what those mods are.
If you move the engine sprocket out and then offset the gearbox there is a chance you may clear a wider tire. You'd have to find a solution for the alternator but that's been done before.
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bwolfie said:
I think I saw it in one of your pics.
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