17" Wheel Conversion
Posted: Tue Nov 14, 2006 8:26 pm
This is from an old old old Paso list posting. I have copied it here to archive it and fix the broken links in the original posts.
Michael T (one of the PASO mailing list members) used the wheels of a 900SS. How he did it? Here's the answer:
I installed the 4.5" rear wheel from a US 900SS/CR (same as your 750SS, but with a 900 engine, I believe). The swingarm is stock Paso 750. The rear caliper bracket had to be made due to the smaller 245mm vs. 270mm rotor. I used the original Paso rear caliper, also. This caliper bracket also serves as a chain line/ centring spacer. My bike came with Marvic wheels a previous owner installed and the axle had to be machined slightly to fit the newer wheel's wheel bearings. I don't know if that was the stock axle or not. Something to look at, though. I use a 160/60-17 rear and 120/60-17 front MEZ2 Metzeler. Those are the stock 900CR/750SS sizes and the ones that come closest to the 160/60-16 and 130/60-16. The sizes on my bike offer very favourable characteristics so far. The front conversion is much the same with the speedo drive requiring a special bushing/ spacer and caliper mounting brackets (for the new calipers to go with the new 320mm rotors). You may or may not need 3/8" spacers between the fender and fork mounts. I put them in 'just in case'. When they did this 17" conversion on the 907ie, they had to add 10 or 20mm to the fork length and limit the travel by a similar amount for the 120/70-17 to clear the coolant radiator. We don't have that radiator, so we can maintain the correct geometry! Ducati admitted they would have liked to use a 120/60-17 on the 907, but the only thing available in '91 were race compound 60 series tires. They 'settled' for the 70 series. As for the rear, a 160/60-17 is all that will fit. The 170/60-17 on the 907 works due to the added width of the swingarm, but because the swingarm is longer, it needs the extra height of that tire (12mm taller) to maintain rear ride height. Hope I hit on all the question areas. It all comes down to careful measuring and having a good working relationship with a machinist/ metal fabricator. But, IT IS WORTH IT in the end!
There is a Paso group in Holland that has done this with pictures of the conversion, I'll post if I can remember where I saved it... Simon Rolfe UK owner of one very unreliable BMW R1100RT. BMW means Break My Wallet! Star-Twin in Loenen sells complete 17" conversion kit's for the 750 sport that should also fit the Paso (according to them) There website is: (can also be found via the ducatilinks on my own homepaso.. er page, I don't know if they sell over-seas, but you could always try.
Dear Derek: Yes, I did the 17" conversion in my Paso and the results are completely satisfactory. I have installed in my Paso a GSXR 1100 wheels: 3,5 x 17 + 120/60-17 + 310mm discs + 4 pistons brakes in front and 5,5 x 17 + 180/55-17 + original Paso disc and caliper in rear wheel. The bike looks very well. Now I can choose a lot of tire models. I can brake hard and my Paso doesn't want to go up (I can brake inside the corners with the bike completely inclined with neutral handling).With 170/60 rear tire the Paso moves better in zig-zag curves but I like the massive look of 180. With this conversion I must to use a 45 teeth rear sprocket. You can obtain Suzuki wheels in used spares shops, the price is good. If you want to know more details I'll be very happy to help you.
I'll try to explain how I do a 17" wheels conversion (sorry but I'm Spanish and my English isn't so good) step by step.
1) You need a pair of 17" wheels (obviously), front discs, calipers and the plate on screw the rear sprocket. Honda, Kawa, Suzuki...it's the same.
2) You must measure the diameter of the 17" wheels axle and the diameter of your Paso. Most of times the 17" wheels axle are thicker than Paso axle. Then you must make a tube with external diameter like a 17" axle and internal one like Paso axle (for this tube I prefer to use stainless steel).This tube must go from the external face of left wheel bearing to the external one of the rigth wheel bearing, crossing coast to coast the hub of the wheel. With this you can use original Paso axles in any wheels (same step front and rear wheel, of course).
3) Now you lift up the Paso with side stand and remove the front wheel and the front mud guard. Then assemble the 17" wheel with Paso axle. Now we need to center this in the fork. I use washers, thick 1 mm and internal diameter like Paso axle. I put washers in both sides of the hub of the wheel, from the bearing to the internal side of the fork. The distance from the edge of the rim to the fork must be the same in two sides. You add washers in the side of minor distance and remove washers from the side of major one, till the distance is the same in both sides.
4) Then you remove the washers and measure the total washers thick for make an aluminium spacer for any side. In left side, you must remember when you measure the washers to discount the thick of the piece of the speedo cable (if you use a 120/60 tire the speedometer shows +/- the same.
5) Rear the sistem is the same, add or remove washers until the distance from the edge of the rim to the swinging arm is the same in two sides of the wheel. Then measure the total washers thick and make an aluminium spacer. You must remember to discount to the rigth distance the measure of the caliper support.
6) When we have the wheels centered we need to mount the front brake discs. First we have to measure the distance from the inner face of left disc to the inner one of the right one in Paso wheel and 17" wheel. If the distance of 17" wheel is bigger than the Paso, you must to rest Paso distance to the 17" distance and the result divide by 2 for obtain the measure that we must to reduce the faces of the hub to align the discs with the calipers. If the distance of 17" wheel is minor than Paso, you must to rest 17" distance to the Paso distance and the result divide by 2 to obtain the measure of the spacers you must make to separe the discs until to align the discs with the calipers.
7) In the rear wheel you must to measure the distance from the center of the hub to the disc face. If 17" measure is bigger you must to reduce the face, the diference of both. If Paso measure is bigger you must to make a spacer of the diference.
When we have the wheels centered and the discs aligned we must to make a calipers suport. I use a piece of wood or plastic to make a model and after I make a piece of stainless steel or duraluminium. I make two holes in the wood piece to screw it to the fork. Then I mount the caliper on the disc and brake, centering the caliper on the disc surface. Then while I am braking turn the wheel until the caliper is nearest possible to the fork and then mark the caliper holes in the wood. With this model of suport I make two metal caliper suports. Screw these to the fork and to the caliper.
9) There are two forms to install the rear discs. You can use the 17" wheel stock disc or use Paso disc. Normally, the 17" disc is more little than Paso disc. In this case you can use the original caliper suport of 17" wheel bike or cut Paso caliper suport to the size of 17" wheel disc and then weld it. I prefer to use Paso rear disc because it is bigger than discs of actual bikes, and more powerful. When we have measured the distance from the center of the hub to the disc face, I reduced this face 10 mm more and make an aluminium disc spacer what I screw to the 17" wheel Hub and the make holes to screw a Paso disc.
10) Normally there is no problem with the chain line. You must to buy a rear sprocket 520 like Renthal or PBR. If your 17" wheels come from a big bike you must to reduce the thick of the sprocket. I use one with 45 teeth because I prefer acceleration to max speed.
11) Finally you must to make four 15mm spacers to lift the front mud guard. Be careful with the tire, It can make a hole in your front mud guard if it rub on it.
Michael T (one of the PASO mailing list members) used the wheels of a 900SS. How he did it? Here's the answer:
I installed the 4.5" rear wheel from a US 900SS/CR (same as your 750SS, but with a 900 engine, I believe). The swingarm is stock Paso 750. The rear caliper bracket had to be made due to the smaller 245mm vs. 270mm rotor. I used the original Paso rear caliper, also. This caliper bracket also serves as a chain line/ centring spacer. My bike came with Marvic wheels a previous owner installed and the axle had to be machined slightly to fit the newer wheel's wheel bearings. I don't know if that was the stock axle or not. Something to look at, though. I use a 160/60-17 rear and 120/60-17 front MEZ2 Metzeler. Those are the stock 900CR/750SS sizes and the ones that come closest to the 160/60-16 and 130/60-16. The sizes on my bike offer very favourable characteristics so far. The front conversion is much the same with the speedo drive requiring a special bushing/ spacer and caliper mounting brackets (for the new calipers to go with the new 320mm rotors). You may or may not need 3/8" spacers between the fender and fork mounts. I put them in 'just in case'. When they did this 17" conversion on the 907ie, they had to add 10 or 20mm to the fork length and limit the travel by a similar amount for the 120/70-17 to clear the coolant radiator. We don't have that radiator, so we can maintain the correct geometry! Ducati admitted they would have liked to use a 120/60-17 on the 907, but the only thing available in '91 were race compound 60 series tires. They 'settled' for the 70 series. As for the rear, a 160/60-17 is all that will fit. The 170/60-17 on the 907 works due to the added width of the swingarm, but because the swingarm is longer, it needs the extra height of that tire (12mm taller) to maintain rear ride height. Hope I hit on all the question areas. It all comes down to careful measuring and having a good working relationship with a machinist/ metal fabricator. But, IT IS WORTH IT in the end!
There is a Paso group in Holland that has done this with pictures of the conversion, I'll post if I can remember where I saved it... Simon Rolfe UK owner of one very unreliable BMW R1100RT. BMW means Break My Wallet! Star-Twin in Loenen sells complete 17" conversion kit's for the 750 sport that should also fit the Paso (according to them) There website is: (can also be found via the ducatilinks on my own homepaso.. er page, I don't know if they sell over-seas, but you could always try.
Dear Derek: Yes, I did the 17" conversion in my Paso and the results are completely satisfactory. I have installed in my Paso a GSXR 1100 wheels: 3,5 x 17 + 120/60-17 + 310mm discs + 4 pistons brakes in front and 5,5 x 17 + 180/55-17 + original Paso disc and caliper in rear wheel. The bike looks very well. Now I can choose a lot of tire models. I can brake hard and my Paso doesn't want to go up (I can brake inside the corners with the bike completely inclined with neutral handling).With 170/60 rear tire the Paso moves better in zig-zag curves but I like the massive look of 180. With this conversion I must to use a 45 teeth rear sprocket. You can obtain Suzuki wheels in used spares shops, the price is good. If you want to know more details I'll be very happy to help you.
I'll try to explain how I do a 17" wheels conversion (sorry but I'm Spanish and my English isn't so good) step by step.
1) You need a pair of 17" wheels (obviously), front discs, calipers and the plate on screw the rear sprocket. Honda, Kawa, Suzuki...it's the same.
2) You must measure the diameter of the 17" wheels axle and the diameter of your Paso. Most of times the 17" wheels axle are thicker than Paso axle. Then you must make a tube with external diameter like a 17" axle and internal one like Paso axle (for this tube I prefer to use stainless steel).This tube must go from the external face of left wheel bearing to the external one of the rigth wheel bearing, crossing coast to coast the hub of the wheel. With this you can use original Paso axles in any wheels (same step front and rear wheel, of course).
3) Now you lift up the Paso with side stand and remove the front wheel and the front mud guard. Then assemble the 17" wheel with Paso axle. Now we need to center this in the fork. I use washers, thick 1 mm and internal diameter like Paso axle. I put washers in both sides of the hub of the wheel, from the bearing to the internal side of the fork. The distance from the edge of the rim to the fork must be the same in two sides. You add washers in the side of minor distance and remove washers from the side of major one, till the distance is the same in both sides.
4) Then you remove the washers and measure the total washers thick for make an aluminium spacer for any side. In left side, you must remember when you measure the washers to discount the thick of the piece of the speedo cable (if you use a 120/60 tire the speedometer shows +/- the same.
5) Rear the sistem is the same, add or remove washers until the distance from the edge of the rim to the swinging arm is the same in two sides of the wheel. Then measure the total washers thick and make an aluminium spacer. You must remember to discount to the rigth distance the measure of the caliper support.
6) When we have the wheels centered we need to mount the front brake discs. First we have to measure the distance from the inner face of left disc to the inner one of the right one in Paso wheel and 17" wheel. If the distance of 17" wheel is bigger than the Paso, you must to rest Paso distance to the 17" distance and the result divide by 2 for obtain the measure that we must to reduce the faces of the hub to align the discs with the calipers. If the distance of 17" wheel is minor than Paso, you must to rest 17" distance to the Paso distance and the result divide by 2 to obtain the measure of the spacers you must make to separe the discs until to align the discs with the calipers.
7) In the rear wheel you must to measure the distance from the center of the hub to the disc face. If 17" measure is bigger you must to reduce the face, the diference of both. If Paso measure is bigger you must to make a spacer of the diference.
When we have the wheels centered and the discs aligned we must to make a calipers suport. I use a piece of wood or plastic to make a model and after I make a piece of stainless steel or duraluminium. I make two holes in the wood piece to screw it to the fork. Then I mount the caliper on the disc and brake, centering the caliper on the disc surface. Then while I am braking turn the wheel until the caliper is nearest possible to the fork and then mark the caliper holes in the wood. With this model of suport I make two metal caliper suports. Screw these to the fork and to the caliper.9) There are two forms to install the rear discs. You can use the 17" wheel stock disc or use Paso disc. Normally, the 17" disc is more little than Paso disc. In this case you can use the original caliper suport of 17" wheel bike or cut Paso caliper suport to the size of 17" wheel disc and then weld it. I prefer to use Paso rear disc because it is bigger than discs of actual bikes, and more powerful. When we have measured the distance from the center of the hub to the disc face, I reduced this face 10 mm more and make an aluminium disc spacer what I screw to the 17" wheel Hub and the make holes to screw a Paso disc.
10) Normally there is no problem with the chain line. You must to buy a rear sprocket 520 like Renthal or PBR. If your 17" wheels come from a big bike you must to reduce the thick of the sprocket. I use one with 45 teeth because I prefer acceleration to max speed.
11) Finally you must to make four 15mm spacers to lift the front mud guard. Be careful with the tire, It can make a hole in your front mud guard if it rub on it.
