Motorcycle Forum banner
1 - 11 of 11 Posts

·
Registered
Joined
·
22 Posts
Discussion Starter · #1 ·
Hi Everyone. I'm not sure where this thread belongs, so I posted this same question in the Vintage group. I'm new here, so if that's not allowed, please tell me. Anyway, I need some help finding the right tire to fit my bike. My 40 year old OEM Rear tire is a Bridgestone 4.10-18. The rim is stamped 1.85. I think that's probably the Rim Width. My question: All the wheel/tire fitment charts I've seen say that the biggest tire you can put on a 1.85" rim is a 3.50. Why can't I use another 4.10 tire? Thanks.
 

·
Swamp Rat Rider
Joined
·
1,918 Posts
When get Rims in Inches and Tires in MM can get confusing On my Dyna I have a 19" X 3" Rim up forward and takes a 100/90/19 Tire.. My Rear is 16" X 3.5" and Takes a 150/80/16 Tire
 

·
Registered
Joined
·
22 Posts
Discussion Starter · #4 ·
It's a 1979 Honda Hawk, 400cc. And yes the Rim Width is 1.85". The rim width is measured from inside the bead. And the tire on that rim is a 4.10-18. But I'm still wondering why all the info I've found says maximum 3.50" (or 90 metric).
 

·
Registered
Joined
·
22 Posts
Discussion Starter · #6 ·
Thanks TriPlay. Those sound like great tires. But here's where it gets tricky. When I go to the Shinko website and enter my Hawk info, the Shinko site says nothing for my bike. No tires. Who should I believe??
Fitment Guide
 

·
Ace Tuner
Joined
·
3,481 Posts
It's a 1979 Honda Hawk, 400cc. And yes the Rim Width is 1.85". The rim width is measured from inside the bead. And the tire on that rim is a 4.10-18. But I'm still wondering why all the info I've found says maximum 3.50" (or 90 metric).
Not many tire makers use the "old way" of measuring tire sizes like 4.10-18, 3.50-18 and the like.
I can't remember the particulars now but the 4.10-18 was sort of an oddity as was sizes like 4.25/85-18.
Those didn't really adhere to the standard American way of measuring tires in inches the way 3.25-18, 3.50-18, 4.00-18, 4.25-18, and so on, do.
There probably are conversion charts, and information, to be found on-line that could explain it better than I can remember that old stuff.

A 1.85" rim will need a fairly tall aspect ratio tire when measured the metric way if you can not find a 4.10-18 to buy.
Something like a 110/90-18 should work.
Maybe ? a larger 120/90 might ? fit the rim well enough if you have swingarm and chain clearance, maybe? ... Not sure about that though.
The "90" in the above metric sizes is the aspect ratio meaning the tire is 90% as tall as it is wide.

It's been a long time since I've dealt with street rims that small so I'm not up on what tire sizes are still available or even what American/metrics will cross over well.
Good luck, I hope this helps.
 

·
American Legion Rider
Joined
·
25,886 Posts
Do any of these tire manufactures give a phone number you could call and get info directly. Or at least get a formula for how to convert. In the end you may have to gamble and just order what some think ?might? work. So I see what their return policy is as well.

I have a local tire dealer that even though she, yes SHE, doesn't do motorcycle tires, she understands tires and will get a tire to try so I can put eyes on a tire and as long as it has never been installed it can be returned. No charge no hassle. She gets enough farm equipment tire charges on me. So look around and see if there is a local tire dealer that isn't a jerk. There are a few like my little jewel. Now her husband isn't too bad but he just isn't as cool. I prefer dealing with her because she at least tries.
 
  • Like
Reactions: CalHawk

·
Registered
Joined
·
22 Posts
Discussion Starter · #9 ·
Thanks for thinking about this SemiFast and hogcowboy and TriPlay and GatorJoe.: I wish I'd never seen those darn tire/rim fitment charts. I've seen 3 and they all agree that the biggest tire you can put on my 1.85" rim is a 90 metric! But the bike came with 4.10s, which is pretty close to a 100 metric! And you guys are talking about 110s! Crazy. Maybe I'll just say the heck with it, and try to come as close as possible to the OEM 3.60-19 Front and 4.10-18 Rear. Thanks again guys.
 

·
Registered
Joined
·
399 Posts
Thanks TriPlay. Those sound like great tires. But here's where it gets tricky. When I go to the Shinko website and enter my Hawk info, the Shinko site says nothing for my bike. No tires. Who should I believe??
Fitment Guide
The Shinko Tourmaster 230 series should have tires to fit your bike. I use them on my '78 Suzuki GS1000E. Back in the day it was common to put one size larger tire on the back. I went one size larger front and back on my bike. Just doing the rear tire has some handling characteristics you wouldn't like.
 
1 - 11 of 11 Posts
Top