« previous next »
Pages: [1]   Go Down

Author Topic: Biggest Rear Tire ? that will go on a 78 cb750f?  (Read 3054 times)

0 Members and 1 Guest are viewing this topic.

Offline joelt85

  • Full Member
  • *
  • Posts: 4
Biggest Rear Tire ? that will go on a 78 cb750f?
« on: October 16, 2011, 03:05:29 PM »
Ive heard of guys putting wider rears on , wanted to know what the biggest size you can put on the rear is without having any interderence , thanks
Joel
Logged

Offline BobbyR

  • Really Old Timer ...
  • *******
  • Posts: 12,365
  • Proud Owner of the Babe Thread & Dirty Old Man
Re: Biggest Rear Tire ? that will go on a 78 cb750f?
« Reply #1 on: October 16, 2011, 03:50:01 PM »
On a 78 you can go at least two sizes over stock with no rubbing. You will notice that the center of the tire will wear flat after a while since the rim is too narrow. You will develop a step between the ecenter tread and the sidewall, when you make a turn you will feel the step. You can find threads covering this in detaol if you do a search. I went down to one size over and the bike handles better.
Logged
Dedicated to Sgt. Howard Bruckner 1950 - 1969. KIA LONG KHANH.

But we were boys, and boys will be boys, and so they will. To us, everything was dangerous, but what of that? Had we not been made to live forever?

Offline DavePhipps

  • Expert
  • ****
  • Posts: 1,150
  • Reading the entire Hi-Perf forum
    • Hillside Technology
Re: Biggest Rear Tire ? that will go on a 78 cb750f?
« Reply #2 on: October 16, 2011, 04:20:42 PM »
I'm running a 110 on the back of my 500 and I'm noticing that the tireis very crowned, almost pointy. Unless you get a wider rim I would stay as close to stock as possible.
Logged
Bikes:
90 FZR600 RA
74 CB550k
78 GL1000
72 CB500K

Offline Gibblet

  • Full Member
  • *
  • Posts: 23
Re: Biggest Rear Tire ? that will go on a 78 cb750f?
« Reply #3 on: October 16, 2011, 05:37:11 PM »
I know it seems better to put a wider tire on, but I would stick with the stock 100 or 110.
Logged
1978 CB750f
1980 CM400t

Offline Roach Carver

  • Really Old Timer ...
  • *******
  • Posts: 6,724
Re: Biggest Rear Tire ? that will go on a 78 cb750f?
« Reply #4 on: October 16, 2011, 07:45:59 PM »
fat tire craze is over, put the right tire size on and you will be happier.
Logged

Offline Stev-o

  • Ain't no
  • Really Old Timer ...
  • *******
  • Posts: 34,461
  • Central Texas
Re: Biggest Rear Tire ? that will go on a 78 cb750f?
« Reply #5 on: October 16, 2011, 08:16:54 PM »
I have a 120/90 on the back of my K4, bought it that way. No problems.
Logged
'74 "Big Bang" Honda 750K [836].....'76 Honda 550F.....K3 Park Racer!......and a Bomber!............plus plus plus.........

Offline DORIGTT

  • Full Member
  • *
  • Posts: 66
Re: Biggest Rear Tire ? that will go on a 78 cb750f?
« Reply #6 on: October 16, 2011, 10:52:30 PM »
What's the reasoning for NOT going with a larger rear wheel / tire combo? 
In looking at the Ducati Sport Classic line, they ran a 120 front (3.5x17 wheel) and 180 rear (5.5x17 wheel).  Not that we'd want to run that size, but a wider wheel out back (how big is the question) and wider tire would fill out the look a bit right?
If you upgrade to the better swingarm bushings out back, fork brace and decent steering bearings, the chassis can take it right?
Logged

Offline Retro Rocket

  • Eggs are hard due too a
  • Really Old Timer ...
  • *******
  • Posts: 19,235
  • ROCK & ROLL
Re: Biggest Rear Tire ? that will go on a 78 cb750f?
« Reply #7 on: October 16, 2011, 11:38:02 PM »
I put a 4.5 inch rear Suzuki rim on the back of my K2 just for a look {same size axle}, it had a 180 slick {wheel came of a 80's GSXR race bike} and it fit in with a tiny amount of room left each side, you would need an offset front sprocket for this to work on the street and probably a 160 street tyre would suffice.


Logged
750 K2 1000cc
750 F1 970cc
750 Bitsa 900cc
If You can't fix it with a hammer, You've got an electrical problem.

Offline TwoTired

  • Really Old Timer ...
  • *******
  • Posts: 21,802
Re: Biggest Rear Tire ? that will go on a 78 cb750f?
« Reply #8 on: October 16, 2011, 11:54:55 PM »
Quote from: DORIGTT on October 16, 2011, 10:52:30 PM
What's the reasoning for NOT going with a larger rear wheel / tire combo? 

If you are using the stock rear rim/wheel (1.85) 4.10x18 is the largest that properly fits it.
If you are changing the wheel rim width to match the tire, then you might consider the chain width (630?) and type of chain guard you are using.

You might state what stock bits you plan to use and how much modification you wish to tolerate/perform.
Logged
Lloyd... (SOHC4 #11 Original Mail List)
72 500, 74 550, 75 550K, 75 550F, 76 550F, 77 550F X2, 78 550K, 77 750F X2, 78 750F, 79CX500, 85 700SC, GL1100

Those that learn from history are doomed to repeat it by those that don't learn from history.

Offline Rigid

  • She likes a
  • Expert
  • ****
  • Posts: 821
  • Speak from personal experience, or don't
    • KingCustomCycles
Re: Biggest Rear Tire ? that will go on a 78 cb750f?
« Reply #9 on: October 17, 2011, 03:54:52 AM »
Quote from: Roach Carver on October 16, 2011, 07:45:59 PM
fat tire craze is over, put the right tire size on and you will be happier.

Actually, fat front and rear are now popular.  I think Exile and the Europeans were ahead of their time on that one.  Of course, the old Harleys used interchangeable tires front to rear and both were "fat" by 1970's Honda standards.  I have used 130-90-18 rear and 110-90-19 front with success on 70's K and F models.  No fender on the front and hardtail on the rear.
« Last Edit: October 17, 2011, 03:57:03 AM by Rigid »
Logged
36 years of this stuff, here to help.

Offline lrutt

  • Expert
  • ****
  • Posts: 916
Re: Biggest Rear Tire ? that will go on a 78 cb750f?
« Reply #10 on: October 17, 2011, 05:11:53 AM »
got a 130 on my K6 for the last bazillion years, Very close to chain guard but no rubbing.
Logged
06 Harley Sporster 1200C, 06 Triumph Scrambler, 01 Ducati Chromo 900, 01 Honda XR650L, 94 Harley Heritage, 88 Honda Hawk GT, 84 Yamaha Virago 1000, 78 Honda 750K w/sidecar, 77 Moto Guzzi Lemans 850, 76 Honda CB750K, 73 Norton 850, 73 Honda Z50, 70 & 65 Honda Trail 90, 70 & 71 Triumph 650s, 65 Honda 305 Dream, 81 Honda 70 Passport, 70 Suzuki T250II, 71 Yamaha 360 RT1B, 77 BMW R75/7, 75 Honda CB550K, 70 Honda CT70

Offline DORIGTT

  • Full Member
  • *
  • Posts: 66
Re: Biggest Rear Tire ? that will go on a 78 cb750f?
« Reply #11 on: October 17, 2011, 09:07:30 AM »
I'd like to run a wider wheel to prevent the 'balloon' effect on the larger rear tires when they are being pinched in .
« Last Edit: October 17, 2011, 04:44:00 PM by DORIGTT »
Logged
Pages: [1]   Go Up
« previous next »