Couple of questions about speed rating; tire size...1800 C

Okay guys...time for me to get serious about the conversion to the DARKSIDE....

Man, seems I've read at least 50-100 threads about this... but let me give you a little background on my bike and what I'm looking for, then maybe you all can help me with answers.

Live in South Georgia...no real mountainous twisties...we do have a few of the S curves, but typically a day riding in the country will involve a few slow rolling curves, a few mildly rolling hills and lots of flat highway.

Speedometer: 2003 1800 VTX-C, currently running a Metz 200 series with about 8500 miles on it...stock gears in final drive...
the reason i know my speedometer is correct is that it was verified by GSP-GA State Patrol...71 in 55... when he zapped me I looked down and my needle was between the 70 -75 area...close enough.

So, that said, I don't want the tire 65,60, 55 affecting the accuracy of the speedometer.

So which one 65 ? 60 ?

Speed rating...I may every now and then get this thing up to about the 100-110 mark and quickly back down... but normally I'm riding 60-70 mph... on an interstate 80mph...

What speed rating should I be looking for.

Tire: Figuring the 205 series... need help (above) on 65,60, etc....what about the brand ??
I'm not really hung up on brand names, but have to admit the Michelin Hydro tread does look good... in all seriousness... mentally I'd probably like to find a tire that does have some tread going up or out onto the sidewall ! LOL... you know not that I'll be dragging knees or anything, but just a comfort zone mentally knowing that tread is there .... especially in my conversion to the D/S....

Tire pressure: I mainly ride 1 up during the week, commutes to/from work... wife and I ride pretty regularly 2 up most weekends.

So basically my questions:
1) What tire height 65, 60, etc will keep my speedometer as accurate as it is now.
2) What speed rating should I be looking for.
3) Tire brand - any favorites ? Just what looks good to you ?
4) Tire pressure ? Just a feel thing ? Somewhere between 35-42psi ?
5) CT rides softer, should possibly be able to come down a notch on my shocks ? Currently on 5.

I know this is a lot of questions... would appreciate ANY feedback anyone can offer... Thanks again !

David V - South GA

I had been researching going to the Darkside for about a year before I did it. As far as what brand of tire, I run the Goodyear assurance tripletred, and so far LOVE that tire. I run it at 43psi and it rides great when the wife and I ride, handles great. It is a 205/60R/16 and this past weekend was out riding with friends and rode beside one and asked what speed he was doing at the time we were side by side and he said 55 mph and I looked down at mine and that was where I was at.So, at this point if my speedo is off it can't be more than 1 mph. Now with my 02 1800C, I ended up raising my shocks, because when we were both on, the tire rubbed slightly, once I did that, no problems. Speed rating go with V or H, H is up to 130 if I remember right, V is above that. You can see the G A TT in my sig pic. Overall, I am glad I crossed over to the Darkside, and I will never go back to a mc tire.

This is the closest you can get to stock with C/T sizes for 1800C with stock size 180/70-16

Specification Sidewall Radius Diameter Circumference Revolutions Speedometer Odometer Difference
~180/70-16~~~~5.0"~~13.0"~~~25.9"~~~~~~81.4"~~~~~~778/mi~~~~~60MPH~~~~10000mi~~~N/A
~215/55-16~~~~4.7"~~12.7"~~~25.3"~~~~~~79.5"~~~~~~797/mi~~~~~61MPH~~~~10241mi~~~-2.4%


Specification Sidewall Radius Diameter Circumference Revolutions Speedometer Odometer Difference
~180/70-16~~~~5.0"~~13.0"~~~25.9"~~~~~~81.4"~~~~~~778/mi~~~~~60MPH~~~~10000mi~~~N/A
~205/60-16~~~~4.8"~~12.8"~~~25.7"~~~~~~80.7"~~~~~~785/mi~~~~~61MPH~~~~10092mi~~~-0.9%

If you want to play with other sizes here is the link:
Tire size calculator

first off , good job Wirehead your first post and you are helping someone.

Hello davidv-soga , I think you and I may have met and shared the road .
As for tires here are some that have a good size for you ...
I take it you want the wide 205/60-16

Goodyear Eagle GT,,,,,,,25.7"

General Altimax HP,,,,,,,,25.7"

Bridgestone Potenza G 019 Grid,,,,,,,25.7"

Yokohama AVID H4S........25.7"

Yokohama AVID T4,,,,,,,,,,,,25.7"

Goodyear Assurance Triple-Tred,,,,,25.7"

Unless you want something that is not as wide.
and there are more (a lot more) on tire rack just click on the specs when you find a tire you like and it will show you the tire measurements .
http://www.tirerack.com/tires/Compare1.jsp?width=205%2F&ratio=60&diameter=16&skipOver=true&y=8&width=205%2F&skipOver=true&ratio=60&diameter=16&x=8&startIndex=0&search=true&pagelen=20&pagenum=1&pagemark=1&RunFlat=All
I live just south of you in Lake Park so if you are looking for a shop to change your tire you can bring your bike to my house and we can remove the wheel and take it to Eagle automotive in lake park and they will change it for you, as far as that goes they have great prices and next day delivary so you get your tire faster.
let me know, your friend,
Horseman

The 65 series in 205 16 has shown best speedo accuracy with stock 1800 gearing by many with GPS testing. Those tire calculators don't take into consideration the stock speedo setup reads 5-10% more than actual, and also the fact sometimes O.D.'s vary in the same size with different tire mfr's. OEM rear Dunlop 180/70/16's O.D. is 26.02", if you go to a 60 @ 25.7" your speedo will read even farther off than with stock tire, or even more than actual.
Less diameter equals more wheel rpm at same speed for higher speedo reading. That's why the 205/65/16 which averages a 26.3" O.D. puts speedo closer to actual than stock.
I wouldn't be concerned about speed rating unless you constantly run over 100+ mph, ratings are for sustained speed over a long distance, not an occaisional blast. The Michelin HE is only T rated 118 and is a well proven CT for mc's. Good luck with your choice

Recent post from OB by 1800C rider :arrow: I ran a 205/65/16 Michelin HydroEdge for about 30,000 miles. This time I mounted a Goodyear TT 205/60/16. I did feel a loss in gearing and now the speedo on my scooter is fast again...faster then actual traveling speed per gps. I wish I would have not decided to try a different tire...I most prolly will run this for a bit, but go back to the HE...Liked the HE that much!

Dan wrote:The 65 series in 205 16 has shown best speedo accuracy with stock 1800 gearing by many with GPS testing. Those tire calculators don't take into consideration the stock speedo setup reads 5-10% more than actual, and also the fact sometimes O.D.'s vary in the same size with different tire mfr's. OEM rear Dunlop 180/70/16's O.D. is 26.02", if you go to a 60 @ 25.7" your speedo will read even farther off than with stock tire, or even more than actual.
Less diameter equals more wheel rpm at same speed for higher speedo reading. That's why the 205/65/16 which averages a 26.3" O.D. puts speedo closer to actual than stock.
I wouldn't be concerned about speed rating unless you constantly run over 100+ mph, ratings are for sustained speed over a long distance, not an occaisional blast. The Michelin HE is only T rated 118 and is a well proven CT for mc's. Good luck with your choice

Recent post from OB by 1800C rider :arrow: I ran a 205/65/16 Michelin HydroEdge for about 30,000 miles. This time I mounted a Goodyear TT 205/60/16. I did feel a loss in gearing and now the speedo on my scooter is fast again...faster then actual traveling speed per gps. I wish I would have not decided to try a different tire...I most prolly will run this for a bit, but go back to the HE...Liked the HE that much!

Reason for me looking for a tire as close to stock size is I have one of the VERY few VTX 1800's that the speedo reads right WITHOUT the use of a speedo healer. I dont know how I got lucky but hey im not complaning. I have checked it with a few GPS units and also with laser rader.

To the OP, I just mounted a Michelin Hydro Edge 205/65/16 on my 2002 1800 C this last last Friday night. I had the exact same reservations as you did. Looked and studied forever. I thought I would wait until my rear tire was gone and at 16000+ I finally needed to get something new on it. So far very happy with it and after having talked to several "tire people" decided the T rating was okay, as they stated the same as above about driving over the speed rating for extended periods of time. It is a tight fit but all went well. I did grind the fender strut down and had to let the air out of the tire to get it on the bike.

My speedometer reads better now than it did before with the stock tires, actually It is right on with my GPS and my buddies Speedometer (on a Harley). Only have about 500 mi. so far but like it alot I don't believe you'll regret putting this tire on.