Went back and forth for a long time on tire sizes and still not sure i made the right choice. Ended up with Avon Road rider 120/80-18s out back and 100/90-18s up front. I like the way the rear looks but I think the front is too tall but I'd welcome the opinion of others. Both tire fit well but I think any wider would be tough, would require removal of caliper to install and possible interference with chain in the rear(especially with the stock 530 chain). Heres a couple of pics to compare the new tires with the old(18x3.00" and 18x3.50").
RD350 project
- Thread starter dugsgms
- Start date
And here is how she looks with her new shoes. Like I said, I like the way the rear looks but I think the front is too tall.
Rode it for a couple of hours this morning and for the most part am happy with the changes, not what I would recommend o a track day but great for thr street. You can definitely feel the gyroscopic force that big front tire has, takes more muscle to get it to turn but by no means too heavy to have fun with. Biggest change is the much higher fell of security of the larger modern tires, feels like I can now give it a handful of front brake and not worry about overpowering the front tire and much more secure in corners. I took one of my normal twisty routes at the same if not faster pace I typically go at and places where the old front tire was starting to protest the new tires didn't feel like they were working at all. Still have a bit of riding to do to make a final decision but so far so good!
Rode it for a couple of hours this morning and for the most part am happy with the changes, not what I would recommend o a track day but great for thr street. You can definitely feel the gyroscopic force that big front tire has, takes more muscle to get it to turn but by no means too heavy to have fun with. Biggest change is the much higher fell of security of the larger modern tires, feels like I can now give it a handful of front brake and not worry about overpowering the front tire and much more secure in corners. I took one of my normal twisty routes at the same if not faster pace I typically go at and places where the old front tire was starting to protest the new tires didn't feel like they were working at all. Still have a bit of riding to do to make a final decision but so far so good!
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Careful With That Axe Eugene
dugsgms said:
It doesn't look too tall to me. looks perfect.
I think you will find the rims and tires fine, though in my experience "the next size down" from the 2.15/2.50 rims and slightly smaller tires than you have chosen seems to be the sweet spot. I like the 90/90 18 or 19 on the front and 110/80 18 on the back, though I haven't tried a 2.50 rear rim with the 120 tire on the back. A 120 tire on the 2.15 rim will assemble but it really needs the wider rim. I've got a new 2.50 rim, just haven't got round to trying it. If I recall the 120 tire I tried needed to be trimmed to clear the chain even with the too narrow rim. The larger tires seem to take a bit of sharpness away from the handling with the combos I've used. I really like the Avon tires and have been using them pretty much exclusively since I bought the first set. I think you have to lean on the bike a little on some bumps to appreciate the brace, but it does help noticeably. I'm a big proponent of a brace and a damper. The rotary stock piece is poor but it does work WAY better than nothing if you rebuild it. Even a crappy piston style is a lot better though. I've come to really like a 19" wheel on the front too as it adds a bit of trail and high speed stability and oddly does not seem to slow the steering, though the bikes I have put he bigger front wheel on had other mods so it is not the most objective assessment. Swapping the forks so the worlds heaviest brake caliper is behind the leg and closer to the steering pivot is one of the better things you can do to improve the handling and stability of these bikes and costs nothing. That will put the speedo drive on the other side and so it will spin backwards rendering the speedo useless, but you can fix that by rounding up a hub from a TX500 which had provision for a second disc. That hub is otherwise identical to the 350's, so you just lace it up and put the disc on the opposite side and bolt it all up like it is now.
Very nice tasteful bike you have there. Never heard of anyone drilling their disc with a hand drill before - you're a dedicated man!
You might find this interesting - I did some similar changes. http://www.dotheton.com/forum/index.php?topic=66498.msg763037#msg763037
Very nice tasteful bike you have there. Never heard of anyone drilling their disc with a hand drill before - you're a dedicated man!
You might find this interesting - I did some similar changes. http://www.dotheton.com/forum/index.php?topic=66498.msg763037#msg763037
sav0r
Coast to Coast
"U" Shaped braces were always marginal. Ones that bridge straight across, not using the stock fork bosses, are much more effective. The brace should not only eliminate flex, but also friction, and with forks friction (especially flexy ones) is everything. I would tend to think that with a good brace and a fair amount of seat time you would be able to tell the difference in a back to back test. I know I can even with the 38mm forks on my RD, but you really have to be riding the crap out of it get there.
CarbsAndCylinders
Careful With That Axe Eugene
Those U-shaped forks did not always fit properly and either pushed the forks further apart from each other or pulled them closer together, increasing sticktion.
Mobius, first off, love the build, pure class!
I think you're right about tire sizes, I almost got the 90/90-18 110/80-18 combo but ended up going with the larger sizes mostly because the front/rear diameter ratio was very close to the factory fitment so was hoping to keep the trail close to factory(I won't lie though, that wider rear tire really appealed to me in the store). To that end I raised the forks in the triple trees to try to make up for the increase in trail due to the taller front tire. In the end though, the increased weight of the new front tire had a larger effect than I expected so all that planning was less effective than I thought. Not that I totally dislike the new handling, its certainly more modern feeling with alot more stability, I just kinda miss the flickability of the factory skinnies. Luckily, my local motorcycle superstore stocks pretty much all the Roadrider sizes at reasonable prices so swapping around should be easy and relatively cheap.
I never thought about swapping the fork legs, great idea and since I've gotten rid of the speedo makes perfect sense for this build. I'm still playing around with fork height next time I make a adjustment I'll swap sides, thanks for the idea!
I"m glad you mentioned that, I thought I was just being anal when I opened up the factory brace quite a bit to just barely touch both forks before assembly, its nice to hear that that additional step may have actually made a difference.
I'll definitively revisit the brace idea, have to do some brainstorming to try to make something effective but still attractive.
Anyhow, thanks for all the input guys, really appreciate it. I should have some more pics this weekend as I plan to make a aesthetic change this weekend.
Talk to everyone later, Doug
CarbsAndCylinders
Careful With That Axe Eugene
http://www.fastfromthepast.com/fork-braces
I have used a couple of these, they do the job. You could probably polish them or anodise them in a brass or copper colour if you don't like the matt black look.
I have used a couple of these, they do the job. You could probably polish them or anodise them in a brass or copper colour if you don't like the matt black look.
Sometimes we have to compromise our principals. From day one I told myself that I'd keep the tach on this bike. While not a neccisity, I alwyas felt it was a nice and practical thing to have on a street bike and so despite what it does to the looks I decided I would leave it on. Well, as time has gone the looks of the tach has gotten to be a bit too much to live with and I decided it had to go. I could justify it by saying that it wasn't very accurate, bounced alot, was heavy and kept rattling it self apart but the real truth is that it was ugly and Id have to make to make the painful admission tha sometimes form wins out in the form vs. function arguement.
Thought about it for a bit and decided the only indicator that I really needed was a nuetral light. I had initially thought I would someday install turn signals but recently resigned myself to the fact that I'd never find a set I like. While I was at it I also decided that I really didnt need a high beam indicator either.
Keeping all that in mind, I made a new dash for the RD. Quickly fabbed up a mount for the ignition switch and installed a LED indicator in the headlamp shell. Used a black rimmed LED so that when unlit would nearly disappear into the background.
Thought about it for a bit and decided the only indicator that I really needed was a nuetral light. I had initially thought I would someday install turn signals but recently resigned myself to the fact that I'd never find a set I like. While I was at it I also decided that I really didnt need a high beam indicator either.
Keeping all that in mind, I made a new dash for the RD. Quickly fabbed up a mount for the ignition switch and installed a LED indicator in the headlamp shell. Used a black rimmed LED so that when unlit would nearly disappear into the background.
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Was mowing the lawn today and noticed the sky was looking somewhat interesting this evening so in order to take advantage of the nice backdrop I took the bike up into the hills to take some pics. Still struggling with making the new to me camera do what I want to do but here are a couple that came out decent.
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Careful With That Axe Eugene
jag767 said:
Gorgeous!
Finally got around to putting a real effort into getting the frame geometry right. The bike handled pretty good for bike of its era(makes my BSA lightning feel like its frame is made of wet spaghetti) but after all the changes was just a bit heavy and hesitant to countersteer correctly. Set sag when I installed the fork springs/cartridge emulators and new shocks and with the help of the adjuster fork caps and was able to get both front and rear sag set correctly(a little closer to race specs than I normally shoot for for but acceptable for a bike primarily being used for playing around in the curvy stuff) but never really got a chance to measure trail.
A preliminary measurement showed nearly 5" of trail and seeing as the spec is 4.17" its easy to see why it didn't want to turn that well. I knew that the increase in tire diameter would increase trail but not .75" so there had to be something more than tire diameter going on. I don't know for sure but I suspect the Hagon shocks I bought are quite a bit shorter than stock greatly increasing trail. Thought about cranking up the preload on the shocks to decrease sag but since it was already pretty short I decided I needed to take another route. At that point, besides offset triple trees I really only had two choices, raise the rear or lower the front. I really didn't want to buy new shocks and since the bike already a somewhat chopper like stance I decided to go for the latter.
While I had the front end disassembled I decided now would be a good time to follow Mobius's advise and swap the fork legs over to move the caliper to behind the fork legs. I doubt it does much but does look alot better(cleans up the front end and bring the visual mass toward center) and should should help with potential headshake at speed. Ended up raising the legs another 15mm and was able to get the trail down to around 4.25".
I was pretty happy with that result and was even happier with the new look. The change brought the front wheel in, eliminated the chopper look and in a happy coincidence, made the bottom to the tank/tail nearly parallel to the ground. But the proof is in the pudding, how would it ride?
Well, I'm happy to report that the changes really helped to eliminate the problems I mentioned before. The bike still takes a bit of effort turn in(likely becuase of the larger front tire) but now coutersteers beautifully and "falls into the groove" quite nicely without alot of work throughout the corner. Still has a bit too much spring rate for a street bike but is really more of a comfort issue than anything else.
I'm still looking into a fork brace. I like the Tarozzi ones but since it appears there's no direct application for RD350 im seeing if a xs650 one will work. Am not in too big of a hurry since I figure the cartridge emulators did more for corner stability that the fork brace could ever hope to.
Here's a before/after of fork height and one of the final stance and new caliper location.
A preliminary measurement showed nearly 5" of trail and seeing as the spec is 4.17" its easy to see why it didn't want to turn that well. I knew that the increase in tire diameter would increase trail but not .75" so there had to be something more than tire diameter going on. I don't know for sure but I suspect the Hagon shocks I bought are quite a bit shorter than stock greatly increasing trail. Thought about cranking up the preload on the shocks to decrease sag but since it was already pretty short I decided I needed to take another route. At that point, besides offset triple trees I really only had two choices, raise the rear or lower the front. I really didn't want to buy new shocks and since the bike already a somewhat chopper like stance I decided to go for the latter.
While I had the front end disassembled I decided now would be a good time to follow Mobius's advise and swap the fork legs over to move the caliper to behind the fork legs. I doubt it does much but does look alot better(cleans up the front end and bring the visual mass toward center) and should should help with potential headshake at speed. Ended up raising the legs another 15mm and was able to get the trail down to around 4.25".
I was pretty happy with that result and was even happier with the new look. The change brought the front wheel in, eliminated the chopper look and in a happy coincidence, made the bottom to the tank/tail nearly parallel to the ground. But the proof is in the pudding, how would it ride?
Well, I'm happy to report that the changes really helped to eliminate the problems I mentioned before. The bike still takes a bit of effort turn in(likely becuase of the larger front tire) but now coutersteers beautifully and "falls into the groove" quite nicely without alot of work throughout the corner. Still has a bit too much spring rate for a street bike but is really more of a comfort issue than anything else.
I'm still looking into a fork brace. I like the Tarozzi ones but since it appears there's no direct application for RD350 im seeing if a xs650 one will work. Am not in too big of a hurry since I figure the cartridge emulators did more for corner stability that the fork brace could ever hope to.
Here's a before/after of fork height and one of the final stance and new caliper location.
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it looks great
if it was mine i would mount some feelers so that you get a warning before those beautiful chambers get flat-rashed at lean angle
remember dropping the front and shorter rear shocks have decreased available lean angle and lowering slows handling
raising the rear is the only viable solution ,really 'cause if you aren't concerned every time you ride it about lean angle and grinding parts on an rd350 you are doing it wrong
if it was mine i would mount some feelers so that you get a warning before those beautiful chambers get flat-rashed at lean angle
remember dropping the front and shorter rear shocks have decreased available lean angle and lowering slows handling
raising the rear is the only viable solution ,really 'cause if you aren't concerned every time you ride it about lean angle and grinding parts on an rd350 you are doing it wrong