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Changing tire diameters?

11K views 12 replies 6 participants last post by  98DARKHORSE 
#1 ·
Has or does anyone change wheel diameter on their bikes?
It can change a personality of a bike. From going from fat bobber tires to a slimmer front for a sportier looked or a more chopped look?
I have an idea to change a front wheel diameter maybe, possibly...

I find I can go from 16" f & r and then change to a 18" or 19" front and keep the same diameter. Keeping the bike height balance the same front to rear, but making the front tire look taller (bigger rim) and having a lower profile tire to pull it off.

Here is RB Racing's tire diameter calculator. Fun to mess with and find ways to change up your bike. Maybe speed up or slow down the steering on your bike?

RB Racing Tire Diameter Calculator

Anyone doing this?
 
#3 ·
WIDE GLIDE came with a 80/21" front stock factory tire & I have changed to a 90/90 21 front tire which is a bit taller & wider which fills in the fender gap nicely and looks & handles a LOT better .
Now , my question is , how much is my speedometer off by ?
 
#4 ·
Unless you have an old cable drive speedo ran off the front tire then your speedo shouldn't have been effected Road.

Read tire diameter will change speedo but can be compensated in several ways.
 
#6 ·
The front tire has nothing to do with reading speed.

I believe your 02 reads speed from the output shaft on the trans. Therefore rear tire diameter will have an effect on accurate speedo reading.

Perhaps someone with more knowledge of an 02 can verify.
 
#7 ·
Speedo drive is off the trans since mid 1990s. Perhaps only the springer softail still maintained the hub drive and a cable drive speedo. All else is electronic. Front tire size will not effect the speedo readings.

Changing the rim size to a larger diameter but maintaining the stock tire height gives the illusion of bigger tire. It uses a smaller size wall which can take away from ride cushioning but reduce sidewall flex and improve cornering and handling.

It can be expensive. Most rims aren't OEM and until recently, you only had the choice 16, 19 or 21 inches. Tire sizes were limited too and until Harley started to use 17s it wasn't until now more options opened up as 17s are popular with the sport bike crowds.

18s make a great substitute for 16s on touring bikes. I had the chance to get 18 inch spoked wheels for my classics and regretfully passed as the price was $500 for the pair......used...with rotors. Some days.... I love this economy.
 
#8 ·
Thanks for understanding the concept Dave. I may end up with a 19" wheel (rim) as it (I hope) could be available as a stock replacement through H-D.
Can stock replacement rims be purchased through H-D?
120/70-19 looks to be the size as the diameter is very close, on a bigger rim, and still look like a fat tire.
But I have to ask myself... should I go for it? :think
 
#11 ·
OK....

HD doesn't make a 19" rim that'll work, unless it's from a spoked wheel, and you have the HOOP laced to a wide glide hub.

THAT can be done, and Buchanan's out of California does that very well.

Buchanan's Spoke & Rim, Inc

They can make you anything you want/need. Blackdog15 had a killer wide rimmed 21" rim done there.

HD doesn't make a cast 19" rim that'll fit, as the only 19 cast wheel they made was for Dyna/XL models, with too narrow of a hub. Your rotors would be set in too far and I don't recommend using spacers for a bike that heavy. (Touring)
 
#10 ·
Yes. You can go to a 140, but it depends on who makes it as the belt will scrape it. Make sure you have no hardware on the inside of the fender rails that stick out as well. I had a 140mm Dunlop on my 1995 Dyna.

In 2004, HD went to narrower belts, and the 140 came stock on Touring models except for the Deluxe. On 2004-2007, you can fit a 150mm if you ditch the lower belt guard or trim it at a minimum.
 
#12 ·
I have my 1200C ordered with spoked wheels!
The Street Bob comes with a 19" rim. If the spoke counts are the same that may be the matching rim I am looking for.
I have used Buchanans before and I would use them again, unless a local dealer happens to build wheels.
 
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