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Blood Sweat Tears and Grease => Wheels Tires and Brakes => Topic started by: fuego on Dec 06, 2018, 13:52:30

Title: Same size and width wheel and tire front and rear?
Post by: fuego on Dec 06, 2018, 13:52:30
I need some help here: I am working on a Nighthawk 250. It has 18" front rim and 16" rear rim. Tires are f:90/100-18, r:120/90-16.

My goal is to replace rear rim to 18". Look less like chopper, more like cb350ish cafe. Easiest method is to find another front rim off the same bike and lace the rim to existing hub. This actually measures out and works! Before I do anything stupid I need some advice from the experts here.

1. Is this safe?

2. Can I have the same tire on the front as well as the back? (just from experience every motorcycle rear tire tends to be wider in general)

3. What about performance?

4. How can i expect the bike to handle after the mod?
Title: Re: Same size and width wheel and tire front and rear?
Post by: irk miller on Dec 06, 2018, 14:45:35
You need a tire that can be used for front and back applications.  They will be listed as such.  It will change your geometry a bit going from 16 to 18, but especially if you run a tire in the rear that is taller than the front.
Title: Re: Same size and width wheel and tire front and rear?
Post by: focusinprogress on Dec 06, 2018, 15:47:36
your factory tire sizes are showing a 2.5% smaller circumference rear tire that's also 20% wider than the front. stick with those percentages give or take to make the least amount of change to overall geometry. the trouble is to get that you're looking at a 120/70/18 rear tire which typically is a front tire size, there's a few that make this size as a rear or as an "either"......but might open up some serious options if you get into a 19" front wheel 18" rear.....then you're into super common sizes f/r like 100/90-19 front 120/90/18 rear.
Title: Re: Same size and width wheel and tire front and rear?
Post by: killerx on Dec 06, 2018, 16:04:24
If all you can find is a front tire in the size you want for the rear, you can flip the tire so it is rotating against the arrow.
Title: Re: Same size and width wheel and tire front and rear?
Post by: Tim on Dec 06, 2018, 17:27:36
Is the diameter of the rear hub about the same as the front?  Same width for the spoke mount flanges?  The angles of the spoke holes in the rim are specific to the diameter and width of the hub.

Buchanan Spokes can get you a set of nice spokes to make it work, if the hub is close to the same as the front hub.  Or, you can get a different rim for the rear.  How many spokes?

Avon RoadRider tires come in 18" universal size for front/rear use.  I had them on my XS650 cafe racer which had 18" rims on both wheels.
Title: Re: Same size and width wheel and tire front and rear?
Post by: zrxxx on Dec 09, 2018, 00:02:59
+1 on the avon roadriders; great tires. Will the taller rear tire clear the swingarm?

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Title: Re: Same size and width wheel and tire front and rear?
Post by: fuego on Dec 10, 2018, 16:25:37
+1 on the avon roadriders; great tires. Will the taller rear tire clear the swingarm?

yes + wanted to get shock to without it looking hedious.

I am planning for avon roadriders :D
Title: Re: Same size and width wheel and tire front and rear?
Post by: fuego on Dec 10, 2018, 16:26:48
Is the diameter of the rear hub about the same as the front?  Same width for the spoke mount flanges?  The angles of the spoke holes in the rim are specific to the diameter and width of the hub.

Buchanan Spokes can get you a set of nice spokes to make it work, if the hub is close to the same as the front hub.  Or, you can get a different rim for the rear.  How many spokes?

Avon RoadRider tires come in 18" universal size for front/rear use.  I had them on my XS650 cafe racer which had 18" rims on both wheels.

it is the same. rims need 36 holes but worried about the angles of the spoke hols on the rims being at an incorrect place.