Author Topic: Big Frackin' Front Tire (Read 3234 times)

ASCSurveyor · « **on:** April 28, 2009, 05:48:35 AM »

Hopefully I won't get too much crap for this...

I like big front tires. Not huge, mind you... like the new batcycle... but maybe something around the size of a stock rear on the CB750. I think it just looks... I dunno... BEEFY. Big, tough, and mean. Am I alone?

Anyway, I know it'll effect the handling dramatically, but I'm not really looking to carve up roads with the bike.

How difficult is it to do this? Do the forks/triple need to be modified in any way? Or is it just a matter of using different spacers for a new axle?

Just doing some research, that's all.

mlinder · « **Reply #1 on:** April 28, 2009, 06:26:23 AM »

Don't think that'll fit inbetween a lot fo the stuff ont he front end. Might be able to do it with no fender, and of course, a larger rim.

Inkscars · « **Reply #2 on:** April 28, 2009, 06:41:11 AM »

I am not running a front fender. Without grinding on my forks, and with a little persuasion, I had to "squeak" my 100/90-19 in there. From what I've found in the manuals, that's bigger than stock. The clearance is close. I also put a 130/90-17 in the rear and it is pretty tight near the swing arm.
I'm sure with some mods you could put larger stuff on there, but that's the largest I could go without and modification (other than fenders).

drdreas · « **Reply #3 on:** April 28, 2009, 07:00:03 AM »

Hey ASC, I'm from Yorktown as well, nice to see someone local on here.

I am currently in the process of outfitting by CB750 K7 with fatter front and rear tires, as I too like the beefy look. There are a lot of folks on here that overstate the difficulty fitting wider tires. With the stock rims you are limited primarily by the width of tire supported by the narrow rims.

I wanted a 17" front rim to get a more modern sporty look, so what I did was remove my stock rear rim (2.5" x 17") from the rear hub, and have re-laced it to my stock front hub. Then I found a 4.5" by 17" harley rim on ebay for $50, and laced that to my rear hub.

I've got both new wheels sitting in my living room, and just received my tires. They're avon roadriders, 120/80/17 for the front, and 150/70/17 for the rear. The 120 will fit up front no problem between the forks on the 77k, and the 150 will fit in the rear with no mods. The rear rim will support up to a 170 tire, but that wide I will have to shift the brake stay to prevent rubbing (very easy mod to do) and MAYBE get an offset sprocket, but it doesnt look like this will be the case.

I also removed my front and rear fenders as I think it cleans up the look greatly. The 120 front tire may not fit with the stock fender anyhow.

ASCSurveyor · « **Reply #4 on:** April 28, 2009, 07:34:41 AM »

Quote from: drdreas on April 28, 2009, 07:00:03 AM

Hey ASC, I'm from Yorktown as well, nice to see someone local on here.

Then a bunch of important stuff...

Wow... 2 '77 750's in Yorktown? We should start a gang. I can make jackets and everything.

Anyway... I'm happy with the size of the rear, so I probably won't go any larger. And the front doesn't have to be as big as the rear, if it's gonna be a big PITA.

I'm not worried about not having a fender. I took the fender off my SV, and think it looks hot, so I figure maybe the CB will be the same. I could always make a larger fender for it, if I really wanted to, I guess.

Are CB wheels hard to find? The spoked ones especially?

Inkscars · « **Reply #5 on:** April 28, 2009, 07:49:04 AM »

Theres alot of guys on here with extra spoked wheels. It seems like they don't like parting with the mags. If you want new and shiny, ask around, there's a guy that sells the wheel and spoke setup powerdercoated the color you want for not too many cheeseburgers.
I think the cbs look better without fenders too, i am gonna use my rear inner fender though because i don't wanna look like a skunk all the time.

I wasn't stating on the complexity of a fatter tire swap. I was just giving you my 2 cents from my experience. Good luck. We want pictures!

vames · « **Reply #6 on:** April 28, 2009, 07:52:36 AM »

Hearing about big front tires always makes me think of this Japanese builder in Las Vegas I saw on TV one time. I don't necessarily love V-Twins but I think his designs are great.

http://www.zero-eng.com/

754 · « **Reply #7 on:** April 28, 2009, 08:06:47 AM »

The forks are pretty thick, run as big as will touch, take a bit off the fork if need be.

If you are running single disc, its easy to get the wheel out, with duals you may have to unbolt a caliper (with a big front tire)

drdreas · « **Reply #8 on:** April 28, 2009, 08:33:04 AM »

I currently live in Boston (went to school here) but still have family there/visit.

120/80 tire will be about as hefty as the stock rear, but this size won't fit on the stock 77 front rim (1.85 x19). You'll need to either find a complete wheel that will mount up to the forks and is at least 2.5" wide (difficult to find), or just lace up a 40 hole rim in the appropriate width (at least 2.5") and whatever diameter you want to the stock hub. I calculated the appropriate size spokes, got a used spoke/nipple set for 50 bucks, and laced and trued the wheel myself.

Cheers

Quote from: ASCSurveyor on April 28, 2009, 07:34:41 AM

Quote from: drdreas on April 28, 2009, 07:00:03 AM
Hey ASC, I'm from Yorktown as well, nice to see someone local on here.

Then a bunch of important stuff...

Wow... 2 '77 750's in Yorktown? We should start a gang. I can make jackets and everything.

Anyway... I'm happy with the size of the rear, so I probably won't go any larger. And the front doesn't have to be as big as the rear, if it's gonna be a big PITA.

I'm not worried about not having a fender. I took the fender off my SV, and think it looks hot, so I figure maybe the CB will be the same. I could always make a larger fender for it, if I really wanted to, I guess.

Are CB wheels hard to find? The spoked ones especially?

Inigo Montoya · « **Reply #9 on:** April 28, 2009, 12:52:59 PM »

I run a 110/90 - 19 on the front. Always have. It clears just fine between fork legs but the fender is a bit close, quarter inch or so.

ASCSurveyor · « **Reply #10 on:** April 28, 2009, 01:53:24 PM »

God I love this place.

I thought about doing the same thing with the SV, and all I got on that forum was [Annoying Bully Voice] I say! You're handling will go strait down the toilet! Surely you must be joking![/Annoying Bully Voice].

Nice to see people who don't care about performance for once.

Inkscars · « **Reply #11 on:** April 28, 2009, 01:56:09 PM »

See the way I figure, I won't know the difference since this is my first bike.

same reason I put clubmans on there to begin with.

KB02 · « **Reply #12 on:** April 28, 2009, 02:55:16 PM »

I agree. I think the big front tire look is pretty cool. I think those choppers you see with a front tire just bigger than a Schwin look silly. My origanal plan for my K8 was a Low and Fat cruiser (that changed). Fat tires all around and just about as low as I could get it.

Once I get the K8 done, I might go back to that thought. Now that I think about it, I really like the idea.

I think this looks pretty cool!

drdreas · « **Reply #13 on:** April 28, 2009, 07:51:20 PM »

Here is one that I used for inspiration for my cb750 custom build I'm now undertaking. Not a CB, but badass!

Burnboy · « **Reply #14 on:** April 28, 2009, 08:06:30 PM »

Im fitting a 130 up front. You ll have to do the gl1000 front end swap to make it fit

KB02 · « **Reply #15 on:** April 29, 2009, 03:59:08 AM »

Quote from: drdreas on April 28, 2009, 07:51:20 PM

Here is one that I used for inspiration for my cb750 custom build I'm now undertaking. Not a CB, but badass!

That is badass. What the heck is that? Or, I should say, what did it start out as?

ASCSurveyor · « **Reply #16 on:** April 29, 2009, 04:45:47 AM »

Quote from: Burnboy on April 28, 2009, 08:06:30 PM

Im fitting a 130 up front. You ll have to do the gl1000 front end swap to make it fit

Thank you. Noted.

I'll add this to "THE LIST".

Quote from: drdreas on April 28, 2009, 07:51:20 PM

Here is one that I used for inspiration for my cb750 custom build I'm now undertaking. Not a CB, but badass!

Very cool. This is the picture I had in my head. Thanks.

themotoworks · « **Reply #17 on:** April 29, 2009, 05:02:23 AM »

I'm running a 120/70-17 on the front, had an extra rear wheel respoked for the front hub, had to machine down the brake bracket to get it closer to the fork tube, but otherwise no serious modifications... will have to replace the face of the speedo with something recalibrated for the new circumference though, or just sharpie a line where 55 is :-D

mystic_1 · « **Reply #18 on:** April 29, 2009, 05:22:18 AM »

If you omit the front fender you'll want to do something to replace the mounting bracket, it does double-duty as a brace, keeping the forl lowers parallel to each other. Without it you'll get some twisting.

You can observe this by standing over the front wheel and clamping it with your legs, then grab the handlebars and twist side-to-side while looking down at the forks. You'll see the twisting near where the uppers meet the lowers.

mystic_1

Inigo Montoya · « **Reply #19 on:** April 29, 2009, 06:05:21 AM »

I would not expect this twisting to be good either as it is dangerous but not only that but I would think that the forks would get wear they normally do not.

drdreas · « **Reply #20 on:** April 29, 2009, 06:27:51 AM »

Quote from: KB02 on April 29, 2009, 03:59:08 AM

Quote from: drdreas on April 28, 2009, 07:51:20 PM
Here is one that I used for inspiration for my cb750 custom build I'm now undertaking. Not a CB, but badass!

That is badass. What the heck is that? Or, I should say, what did it start out as?

Believe it or not, it started as a 1981 Yamaha XV750 Virago. It was one of the few years they made the bike with a monoshock, hence why it was used for this project. The builder is from the Netherlands.

ASCSurveyor · « **Reply #21 on:** April 29, 2009, 07:15:10 AM »

Quote from: roccitycafe on April 29, 2009, 05:02:23 AM

I'm running a 120/70-17 on the front, had an extra rear wheel respoked for the front hub, had to machine down the brake bracket to get it closer to the fork tube, but otherwise no serious modifications... will have to replace the face of the speedo with something recalibrated for the new circumference though, or just sharpie a line where 55 is :-D

Speedo?

I kid. I'd like to keep the guages. 1/2 of me wants to keep it "retro", with analog guages, drum brake, etc... and the other 1/2 wants to add a little technology to it... something like some nice KOSO guages, fully adjustable rear shocks, etc. But I got quite a ways to go before I get there.

Quote from: mystic_1 on April 29, 2009, 05:22:18 AM

If you omit the front fender you'll want to do something to replace the mounting bracket, it does double-duty as a brace, keeping the forl lowers parallel to each other. Without it you'll get some twisting.

You can observe this by standing over the front wheel and clamping it with your legs, then grab the handlebars and twist side-to-side while looking down at the forks. You'll see the twisting near where the uppers meet the lowers.

mystic_1

Good to know. Could one fab a brace to stiffen up the forks a bit, perhaps a few inches above the tire?

mystic_1 · « **Reply #22 on:** April 29, 2009, 08:49:00 AM »

Sure, choppers often run those but the problem is that they clamp to the fork UPPERS which isn't nearly as effective as connecting tops of the for LOWERS.

Some people just slice the rivets off the stock front fender and re-mount the bracket, others have found good braces on the aftermarket. Search up "fork brace" and see what some of the other guys here have done.

mystic_1

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Author Topic: Big Frackin' Front Tire (Read 3234 times)