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Thread: Lowering 1982 R100RT

  1. #1
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    Lowering 1982 R100RT

    Has anyone lowered a 1982 R100rt or similar bike? I can take the 3/4" spacers out of the fork tubes that are on top of my progressive springs to lower the front. I have Koni 7610-1298 shocks on the back with 222 springs. My options on the back is a softer spring or new Ikon shocks that are made for an R65, about .4" shorter. I know I'll have to shorten my ride off stand a bit and this is ok with me. I know its not much but i'm looking for whatever i can. Anybody have any feedback, positive or negative?
    Thanks,
    Jim O'Coin
    1982 R100RT
    1971 R75/5

  2. #2
    Administrator 20774's Avatar
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    What tires do you use? Metric tires are lower profile. I'd consider a seat modification first before making suspension mods.
    Kurt -- Forum Administrator ---> Resources and Links Thread <---
    '78 R100/7 & '69 R69S & '52 R25/2
    mine-ineye-deatheah-pielayah-jooa-kalayus. oolah-minane-hay-meeriah-kal-oyus-algay-a-thaykin', buddy!

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    Seat and tires

    I have a corbin seat that is about as low as i can make it (already modified) and my tires are the recommended inch versions. The back one is brand new.

  4. #4
    Administrator 20774's Avatar
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    Quote Originally Posted by ocoinji View Post
    my tires are the recommended inch versions. The back one is brand new.
    Inch-sized tires have a higher profile than metric tires. Depending on manufacturer, they can be 0.5 inches smaller in radius. I noticed that when I ran metric tires on my /7. The side stand was basically useless on level ground...the bike sat up so straight with the stand out...that's because the bike was lower to the ground. Now with inch-sized tires, things are back to normal...bike sits higher.
    Kurt -- Forum Administrator ---> Resources and Links Thread <---
    '78 R100/7 & '69 R69S & '52 R25/2
    mine-ineye-deatheah-pielayah-jooa-kalayus. oolah-minane-hay-meeriah-kal-oyus-algay-a-thaykin', buddy!

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    Rear shocks from R65

    Does anyone have some still functional shocks from an R65 that i can try (borrow) come springtime to see if this will work for me? I don't want to spend a bundle on new shocks only to find out that i don't like the change. I'll return the borrowed shocks when i'm done with them.
    Thanks,
    Jim

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    lLowering the RT

    Being significantly vertically challenged I had to lower my RT and ended up getting about 2 1/2 inches. Using shorter Konis lowered the rear, along with the lower profile tires. Progressive makes a shock that is a whole inch shorter and it will work fine. You do want to lower the front end a similar amount and I used a San Jose billet triple clamp, machined out the upper stop so that the fork tube would slide right through without having to be cut and gained a good inch there. The big gain item is the seat. I cut out about 2/3 of the foam on the front part, reshaped it and put in a thin gel pad to provide a little comfort. If I let the bike lean a little when I stop I can get my foot flat and I'm down off my tip toes. The stock side stand has to be replaced because it now holds the bike too upright so a Brown is necessary. Also, the center stand is too tall and there's no way I can get it up by myself when it's got all the luggage on and a full tank of gas.

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    Front suspension

    Thanks for your suggestions. I'll look into the billet triple clamp. I heard the same comment from another person. Did you have to do anything to the rear fender for tire clearance?

  8. #8
    Registered User lkchris's Avatar
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    Quote Originally Posted by 20774 View Post
    What tires do you use? Metric tires are lower profile. I'd consider a seat modification first before making suspension mods.
    A lower profile tire IS a suspension mod.
    Kent Christensen
    21482
    '12 R1200RT, '02 R1100S, '84 R80G/S

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    lowering the RT

    Rear fender clearance is tighter but no fender mods were necessary. You give away some clearance with the shorter shock but get some back with the lower profile tire.

  10. #10
    Registered User bmweuro's Avatar
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    I have lowered a lot of BMW's over the years for customers that are vertically challenged. San Jose BMW made a few alloy upper triple clamps that allowed you to move the fork tubes up, throw away the progress fork springs and replace them with stock BMW and contact the US Icon distributor for a shorter spring for your Koni shocks. Have a custom seat made that is very narrow at the gas tank so you can keep your legs close to the bike when you come to a stop.
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