GSXR rear wheel swap: Sprockets, tires, gearing (sorry)

[TheRadBaron]

First, I'd like to apologize for posting this question when I'm sure that the answer is on the board somewhere.  I have really slow rural internet and it's brutal trying to search through all the information here. 
Anyway, I'm assembling the pieces to swap a 17x5.5 GSXR1100 rear wheel onto my '84.  I'd like to keep the final gearing close to the original '84 specs, but I don't know how the diameter of the 17" tire compares to the old 16".  I'd like to know what size rear sprocket to get.  I know that there will be some change, so I'd like to err on the side of cruising RPMs going down rather than up.
Also, what is the best tire size to use on this swap?  I'm not concerned with having the widest tire I can cram into the frame, and I'd rather not deal with a "this size Brand A tire fits, but the same size Brand B tire rubs" scenario.
Also, what's a good modern sport touring radial tire, with an emphasis on "touring".  I hate to say it, but living in central Illinois, corners are few and far between.  I'm more concerned with long lasting tires than knee-dragging cornering ability.  I put a lot of miles on the FJ on the highway and cornfield grid roads.
Thanks a lot.

[SlowOldGuy]

Wow, thats a lot of conditions.

Question: Why did you go to the trouble of doing the conversion?  You don't appear to be interested in any of the benefits.  Sounds like you should have just kept the stock wheel and used a Dunlop D401.  I got a ton of miles out of one of those.

DavidR.

[racerman_27410]

the overall diameter of the 17" wheel with tire is almost exactly the same as the 16" wheel with tire.

[FJmonkey]

the overall diameter of the 17" wheel with tire is almost exactly the same as the 16" wheel with tire.

Yep, what he said......

[TheRadBaron]

Thanks for the good info, racerman and fjmonkey.  I'll just keep the stock gearing.
That being said, Slow old guy, I think that you're making a lot of assumptions as far as my motives go.  
There are a few reasons why I'm doing the swap.  One reason is for wider availability of tires.  I'd like to be able to choose from a number of  modern tires that can offer more grip and mileage than the tires available for the somewhat obsolete 16" front and rear tires that I have now.  Don't misunderstand my first post.  I am still concerned with good grip and handling.  I do manage to find some curves out here and let 'em have it. That's why I asked for a "sport touring" tire on the touring end of the spectrum.  I didn't ask "do Goldwing tires fit on an FJ"?.  But I'm also not looking for a "sport touring" tire that's designed for very aggressive riding at the expense of mileage.  You can't tell me that I can find a tire in the original 16" size that can provide the benefits of a cutting-edge tire design available in 17" sizes.
Another reason I'm doing the swap is that I understand that the 17" wheels (arguably) provide much better handling.  Again, my area is lacking a lot of good, curvy roads, but I do enjoy going around the ones that I can find (at high speed).
Yet another reason is that I changed to a 17" front wheel as well.  Even if I don't have any other "legitimate" reason to want a 17" front wheel, the upgraded blue dot brakes are certainly a benefit that I'm interested in.  So I wanted a 17" rear to match.

[SlowOldGuy]

I didn't make any assumptions. I simply read the following paragraph.  I really liked the 16 inch D401.  It was one of the longest lasting tires I have ever run. Also performed as well as any radial I've tried. 

From your stated "requirements" I was simply giving you my best answer.  I have yet to find a 17" tire that gives the mileage/performance equivalent of that Harley tire.

Also, for the record, my stock 2-piston calipers with Ferodo pads were just as good as the monoblocs that replaced them.  I do still have the 5/8ths master.  But I'm not a big fan of overly sensitive brakes anyway.

DavidR.

Also, what's a good modern sport touring radial tire, with an emphasis on "touring".  I hate to say it, but living in central Illinois, corners are few and far between.  I'm more concerned with long lasting tires than knee-dragging cornering ability.  I put a lot of miles on the FJ on the highway and cornfield grid roads.
Thanks a lot.

[Alf]

the overall diameter of the 17" wheel with tire is almost exactly the same as the 16" wheel with tire.

Well, guys, if maths don´t lie to me, the overall 16" rim with tyre diameter is 646 mm and 636 mm with a 170/60/17 and 630 with a 180/55/17
In fact with the mod done you can feel the rear like a custom bike and a shorter dogbones are essential to a flickable handling

[Alf]

First, I'd like to apologize for posting this question when I'm sure that the answer is on the board somewhere.  I have really slow rural internet and it's brutal trying to search through all the information here. 
Anyway, I'm assembling the pieces to swap a 17x5.5 GSXR1100 rear wheel onto my '84.  I'd like to keep the final gearing close to the original '84 specs, but I don't know how the diameter of the 17" tire compares to the old 16".  I'd like to know what size rear sprocket to get.  I know that there will be some change, so I'd like to err on the side of cruising RPMs going down rather than up.
Also, what is the best tire size to use on this swap?  I'm not concerned with having the widest tire I can cram into the frame, and I'd rather not deal with a "this size Brand A tire fits, but the same size Brand B tire rubs" scenario.
Also, what's a good modern sport touring radial tire, with an emphasis on "touring".  I hate to say it, but living in central Illinois, corners are few and far between.  I'm more concerned with long lasting tires than knee-dragging cornering ability.  I put a lot of miles on the FJ on the highway and cornfield grid roads.
Thanks a lot.

Take a look to my web. This is the conversion that I´ve done. You have detailed info inside
Regards
Alf

[markmartin]

I used the chart on this link to find tire diameter in inches.

http://www.stevenott.com/tyresizes.htm

150/80x16  = 25.45"

170/60x17  = 25.03"

I'm going with the stock 17 countersprocket and going to drop down to a 38 rear.  Like you, I'd like to get on the cruising side of the ratio.  I haven't done the math to know the exact difference this will be to the original gearing.

[Dazza57]

TheRadBaron, go to the Files section, child boards, gearing files, there is a spreadsheet that does all the maths for you. I think I got the link right, haven't worked out how to do that yet. BTW, I went with 38/18 on my 1990, dropped the revs nicely, now about 3800 at 110kph, just over 5000 at 160kph. Down side is I find myself in 2nd and 3rd around town up to 70kph, not such a bad thing to get the lower revs when cruising on the hwy.

Cheers, Dazza

http://www.fjowners.com/index.php?topic=583.msg4274#msg4274

[Alf]

Please, mates, where have you find a 38 GSXR rear sprocket?. I had to special order a JT one because I can only find 43-44 ones

[Arnie]

As stated the overall diameter is only slightly smaller with a 170/60x17.  Means ride height is 1/4" lower.
There are no "dogbones" on the '84 so if you want to raise the ride height you'll have to get a shock that is longer or has adjustable length.  Optionally, you could lower the front by that amount (or a bit more).

I've been running a GSXR wheel for about 12 years and have never found a rear sprocket smaller than 42.
So, I run a 18t countershaft sprocket with that 42 rear.
As for tires, a lot depends on what you like.  I've been happy with Bridgestone BT020, Pirelli MTR04, Metzler Z6, and Michelin PR2 (which I have on currently).  I've also got another PR2 to put on when I wear this one out.  I get 14-16,000 kms out of rear tires (8500-10,000 miles).

Cheers,
Arnie

[markmartin]

     .>>>>    and have never found a rear sprocket smaller than 42.  <<<<<

JTR816.38      This is the JT number for the 38 tooth / 530 sprocket that I found for the GSXR wheel.

http://www.jtsprockets.com/catalogue/sprocket/JTR816-38


I found the previous link on this page;   http://www.jtsprockets.com/catalogue/model/5833  which lists the sprocket as a '530 chain conversion' for the GSXR for model years '89-'92.  I've got a '90 GSXR-1100 Rear Wheel.

I haven't ordered it yet.  I'd love some confirmation from the forum that this is a viable option.  ?

[markmartin]

Doh!  Gear ratio chart on this same page if you scroll down a bit.

http://www.jtsprockets.com/catalogue/model/5833

...assuming that the sprocket selection I'm looking at is a workable option.

[Alf]

There are no "dogbones" on the '84 so if you want to raise the ride height you'll have to get a shock that is longer or has adjustable length.  Optionally, you could lower the front by that amount (or a bit more).

I've been running a GSXR wheel for about 12 years and have never found a rear sprocket smaller than 42.
So, I run a 18t countershaft sprocket with that 42 rear.

It is true!!!!. Sorry, I missed it

Good combo that 18/42. I want to fit a Supersprox rear, so I will ask for it

If you like the 17/40 combo (a little shorter than the OE with 16") you can order to JT. It is not expensive apart from paying in advance