lacing in wider rims, tire widths ?'s

[Chuck78]

After consulting the Avon AM26 Road Rider spec sheets, see now that according to them, even running a 120 rear tire is a bit wide for the 2.15 stock rim. And to think I was hoping to stuff a 130 on the stocker to get better traction...

Even to run a 130, they recommend a 3 inch minimum width rim, 3.5 ideally.
they offer these rears that seemed appealing to me:
Size - width - diameter - rim width range
130/70/18 - 133mm/5.2" - 649mm/25.6" - 3-4" (MT3.50)
140/70/18 - 142mm/5.6" - 666mm/26.2" - 3.5-4.5" (MT3.75)
150/70/18 - 154mm/6.1" - 658mm/25.9" - 3.5-4.5" (MT4.25)

I think stock was:
4.00-18 - 116mm/4.6" - 671mm/26.4" - 2.15-3" (MT2.50)

As far as fronts, I have a 19" rim which I now realize it harder to find tires in! The stock front rim width (2.15 also????) seems fine for a 100 or 110 tire, as I didn't remember seeing a 120 in either 18 or 19. I did jot down in my notes that the original front tire diameter if it was a 3.25 as I suspected, was 26.1"/664 diameter. Avon offers:

100/90/19 - 109mm/4.3" - 671mm/26.4"
110/90/18 - 116mm/4.6" - 663mm/26.1"
Both are recommended for a 2.15" rim. If I swap to an 18 and I was right on the original tire diameter, my speedometer it would be the most accurate with the 110/90/18, but maybe I could settle for the 100/90/19 in order not to have to relace my front wheel $$$$$.

The slightly wider tire would be cool & the more accurate speedometer even cooler, but new rims are quite expensive! I may just do a mirror polish on an aluminum rear rim to match the chromed steel front when my rear tire gets bald next year...

Does anyone have any tips on a good affordable sources for aluminum rims? Any feedback on tire sizes?
I don't know if it's worth it to go to a 4.25 rim and run a 150 rear tire, but I do have a GS 1100 swing arm to install on my bike that will give me a little extra clearance. The 140 tire on a 3.5" rim will give me slightly more sidewall angle, but I think it's close enough. According to Avon (&lack of availability of 3.75 rims), seems as if the 130 fits a 3.5" rim perfectly, & the 150 fits a 4.25 rim perfectly. The 140 on a 3.5 is still acceptable by their standards but slightly narrower rim than an exact ideal fit.

Also the other thing that I had it in the back of my mind is at what point would I need offset or spaced out sprockets??? 150 I would imagine is pretty darn close to having chain clearance issues.

As of now I think I'm going to skip the racetech cartridge emulators for the front shocks and invest in 1 or 2 aluminum rims and wider tires to improve handling & appearance.

This will be a 920cc 10:1 GS750 engine w/4-1 exhaust & k&n filters etc. As it is now with the Wiseco 844 kit in it & a half bald Kenda Challenger 110/90/18, I have to be pretty careful on the throttle when turning at lower speeds In order to not start spinning the tire & slide out! I want it to corner better and also have more traction for accelerating, especially in turns!

Feedback on tire size versus handling results is much appreciated, well as tips on what rims and where to buy. Sun & Excel seem to be the only two I see all over. Maybe the swap meet at AMA vintage motorcycle days next summer couldfind me some deals but otherwise I'll expect to be paying a small fortune :-(

 

[SqDancerLynn1]

The GS rims were not designed for radials. Sounds like you need to update your wheels. Do the necessary modifications for fitment..

 

[Chuck78]

That's what I'm talking about, sorry for the lengthy post that is uninviting to read, I'm looking to lace up a wider aluminum rear rim, probably a 3.50 WM6, but maybe a 4.25.

 

[SqDancerLynn1]

This is a 2 valve 750 ???? The 1100 swing arm will help You also need to convert to a 520/530 chain ? and an offset front sprocket. Get a complete GS 1100 90's vintage front end..

http://www.buchananspokes.net /??? for wheels

 

[Chuck78]

Yes, 1977 gs750 2v soon to have 1979 gs850 cylinder block & 72mm MTC Engineering 10:1 pistons. I wanted the biggest kickstart gs engine I could reasonably get, & the NOS big bore pistons practically fell into my lap fortunately.

I wasn't sure if a 140 would warrant an offset sprocket but I suppose I could measure my current tire & chain position to see. I will need a longer chain anyways due to the GS1100 box aluminum swing arm swap, & was considering a conversion to 530. What should I look for in an offset sprocket as far as supplier or sourcing from another bike? Does anyone have a link to a chart for sprocket tooth count conversions?

I looked briefly for GS 1000 or 1100 Front ends but I wasn't aware that the late model was a good swap. I was looking to keep my current original wheel setup (well, hubs- need to stay with spoke wheels). I got a gs650g fork which has the exact same width as the '77 750 forks. I think a 110 or 120 will fit fine as I have clearance left over with a 100/90/19

 

[blowerbike]

if you go wider on the rear rim you will need to add a spacer behind the sprocket to move the chain away from the tire.
you may be able to spay with a flat front sprocket but in theory whatever you add in the rear needs to be added to the front.
if you look around racers sometimes start out with a WM6 rim.
these are 3.5x18 and are available used for fair prices at times and they use a stock wire GS disc. hub.

you can run a 150/70/18 on a 3.5 if a tire is available.
if you was going mags..and 85/86 1150 rim is a 3.5x17 and will bolt right on with minimum modifications and you could find an 83 1100E front rim to match.

 

[Big T]

Cheap option - get the 4.00-18 rear and 3.25-19 front Avons, I did and they work fine. In fact ,better than the metric sizes

Wider wire wheels - expect to pay about $1,000 for rims and lacing plus new tires. You can't go radial with wire wheels. You'll need the wider swingarm

Wider wheels - the easiest way is a GSX or GSXR front end from the 90's, the rear wheel, the GS1100 swingarm, a chain conversion with offset sprocket and some fabrication. Depending on what kind of deal you can get, expect $700-$1,500

 

[John Kat]

You can easily fit a 160*18" tire in a gs 1100 swingarm.
I've tested it on my 1100 Kat.
The sprocket will have to be offset by 13 mm to keep the chain aligned.
Here I've used a 1st gen GSXR 18*4" wheel.
On the picture the wheel is mounted left to right as I was testing the alignment

 

[850 Combat]

Cheap option - get the 4.00-18 rear and 3.25-19 front Avons, I did and they work fine. In fact ,better than the metric sizes

Wider wire wheels - expect to pay about $1,000 for rims and lacing plus new tires. You can't go radial with wire wheels. You'll need the wider swingarm

Wider wheels - the easiest way is a GSX or GSXR front end from the 90's, the rear wheel, the GS1100 swingarm, a chain conversion with offset sprocket and some fabrication. Depending on what kind of deal you can get, expect $700-$1,500

Yeah, Todd, but they look bitchen. I just had The Wheel Works build me a set for my MK II Commando. The polishing of the hubs is awesome. I think I have like two grand in them.

Wheel Works used to be Junky Nicks until these guys bought it thirty years ago.

 

[Chuck78]

I checked my clearances this evening. My balding 110/90/18 measures about 4.4", and with the bike leaning on the side stand and a loose chain, I speculated that I had 1" clearance to the tire (chain might have been a little further away due to lean on stand side).
In the Avon AM26 Roadrider, a 140/70/18 is 5.6" wide on the proper rim (3.50"+). I think this would work really well, and leave me about 1/2" clearance to allow for some side to side chain slap, but I'd have to keep on top of chain tension adjustments to not allow it to get too loose and sloppy side to side.

With a 150/70/18 rear AM26 Road Rider at 6.1" wide, there would be very minimal clearance, and I'm afraid the chain would slap sideways on cornering and contact the tire. With this I'd probably say you need to go with an offset sprocket setup for sure.

I also noted that the stock rims on my 77 GS750 are 2.15x18 rear and 1.85x19 front, so that puts me in the market for two rims to get the proper sidewall angle for elimination of squishy cornering with too narrow of rims for the wider tires. These rims being as narrow as they are is why BigT and others will tell you that the original OEM tire sizes work the best, because any wider tire is getting squeezed in by the skinny rim, and the factory sizes were maybe one size shy of the widest tire you can fit on those rims without squeezing the tire in and distorting the tread profile, and also causing squishy squirmy handling. This is why even if I decide to run a 130 front and 100 or 110 front, I will still be lacing in 3.00-3.50 and 2.15-2.50 alloy rims

I may try and pick up some GS hubs and re-lace new rims and spokes, so I can sell my good stock wheels as-is. Anyone have any spare hubs? I don't care if they need new bearings.

 

[Chuck78]

a quick comparison.

Avon AM26 Road Rider rears:
$147 140/70/18 5.6" wide 26.2" diam (3.5-4.5" rim, 3.75 is best)(closest to the stock 26.4" diameter)
$115 150/70/18 6.1" wide 25.9" diam (3.5-4.5" rim, 4.25 is best)

Avon AM26 Road Rider front:
$109 110/90/18 4.6" wide 26.1" diam (closest to stock 26.1" for speedo accuracy)
$109 110/80/18 4.4" wide 25.2" diam
$104 100/90/19 4.3" wide 26.4 diam (could use same spokes and even re-lace rear 2.15x18 to front hub, budget build)

seems the cost of wider rim and offset sprockets will be offset by the $40 tire savings going with the wider 150 rear.
In the front you have to choose between speedometer accuracy with the taller 90 series (I'm assuming a 3.25x18 is the stock oem size), and a shorter sidewall for stiffer ride and less tire flex in hard cornering with the 80 series.

 

[Chuck78]

Now for a highly regarded budget tire... They are mostly 90 series and limited widths, but the price is much better and GS Resources members highly recommend them.

Shinko SR741 rear
$77 140/70/18 (?" wide ?" diam?? probably about 5.4" wide and 26" diam)

Shinko 230 Tour Master rears
$81 120/90/18 (4.69" wide 26.5" diam recommended 2.75" rim)
$83 130/90/18 (5.08" wide 26.8" diam recommended 3.00" rim)

Shinko 230 Tour Master fronts
$68 100/90/18 (3.98" wide 25.08" diam recommended 2.5" rim)
$81 120/90/18 (4.69" wide 26.5" diam recommended 2.75" rim but same size in Avon says 2.5" or 3" rim)
$67 110/90/18 (4.29" wide 25.79" diam recommended 2.5" rim)(much smaller than the same size in Avon's)
$65 110/90/19 (4.29" wide 26.81" diam recommended 2.5" rim)
$65 100/90/19 (3.98" wide 26.10" diam recommended 2.5" rim)


The Shinko's and Avon AM26's are both superb V-Rated (149+ mph) tires, Shinko seems to be a little more of an off-brand with less sizes available, but if you want these sizes, they are the hot ticket for sure. I think I would be leery of the 130/90 Shinko, as an 80 with the shorter sidewall would be good by me, but a 130/90 is going to be a fairly tall tire. the 120 would fit perfect on a common 2.50-3.00x18 rim, but no wider. It'd squeeze on a stock rear rim, but again, not ideal, 2.5" minimum according to Avon for their 120's.

 

[Chuck78]

Looks like about $144 for the Shinko 230/SR741 combo, $224 for the AM26's with 150 rear ($need to offset sprockets$) and $257 for the AM26's with a 140 in the rear.

I've been reading some reviews, and it seems that the Shinko's grip REALLY GREAT and corner quite well, but wear down in 5,000-8,000 miles. Users typically say they are a GREAT value for the money.
it seems that the Avon's are obviously wider than average for their stated size, and that they grip pretty well. A few complaints about cupping/uneven wear and cracking/checking on the sidewalls, but they last 7,000-12,000+ miles and grip great.
So I'm going to jump to conclusions and say that the Avon's will last almost twice as many miles, and have a wider contact patch, but the Shinko's will grip slightly better and possibly do better in the rain. The avons (and offsetting sprockets) will cost just under twice as much as the Shinko's but last close to double as long. Even toss up I suppose other than more frequent labor to mount the shinko's at annual change intervals.

 

[blowerbike]

I checked my clearances this evening. My balding 110/90/18 measures about 4.4", and with the bike leaning on the side stand and a loose chain, I speculated that I had 1" clearance to the tire (chain might have been a little further away due to lean on stand side).
In the Avon AM26 Roadrider, a 140/70/18 is 5.6" wide on the proper rim (3.50"+). I think this would work really well, and leave me about 1/2" clearance to allow for some side to side chain slap, but I'd have to keep on top of chain tension adjustments to not allow it to get too loose and sloppy side to side.

With a 150/70/18 rear AM26 Road Rider at 6.1" wide, there would be very minimal clearance, and I'm afraid the chain would slap sideways on cornering and contact the tire. With this I'd probably say you need to go with an offset sprocket setup for sure.

I also noted that the stock rims on my 77 GS750 are 2.15x18 rear and 1.85x19 front, so that puts me in the market for two rims to get the proper sidewall angle for elimination of squishy cornering with too narrow of rims for the wider tires. These rims being as narrow as they are is why BigT and others will tell you that the original OEM tire sizes work the best, because any wider tire is getting squeezed in by the skinny rim, and the factory sizes were maybe one size shy of the widest tire you can fit on those rims without squeezing the tire in and distorting the tread profile, and also causing squishy squirmy handling. This is why even if I decide to run a 130 front and 100 or 110 front, I will still be lacing in 3.00-3.50 and 2.15-2.50 alloy rims

I may try and pick up some GS hubs and re-lace new rims and spokes, so I can sell my good stock wheels as-is. Anyone have any spare hubs? I don't care if they need new bearings.

i have 1 or 2 front hubs only..bare no bearings or anything...drilled factory dual disk.
pm me if interested.

 

[Guest]

Hi, major thread revival!

Chuck which way did you go with rims in the end?

I'm planning similar on my gs750 with a standard gs1000 swingarm.

I have been considering lacing a standard rear rim onto the front hub and lacing a wider rim onto the rear hub.

If you went to 18 on the front was it simple to lace new shorter spokes to the stock hub?

How wide a rim did you manage to go on the rear?

Any other info gratefully received too!

Thanks