nycbusi

Hi

I hope this is the right section to post. Apologies if it is not.

I currently am riding a 2007 Jamis Ventura Comp : 2007 Jamis Ventura Comp - BikePedia

The tires are 700x25c. I want to convert it in to a touring bike and put on some larger tires for roads that have loose soil/sand, possibly some loose gravel, possibly hitting a pothole or two, but no offroading or trails. More for a 3rd world country pavement.

How can i determine what is the max width tire size that will fit in the frame? I'd love to get at the minimum a 26x1.76 in there if poss.

Thanks for any help.

-Steven

trailangel

26 would require new wheels and brakes. I don't think you will be able to fit that wide a tire.
Have you measured? The bike is there with you and not here.

HillRider

Unless you have disc brakes, and from the link you provided, the bike doesn't, 26" wheels aren't going to work, no matter what tire size you choose. You have to continue to use 700c wheels and try-fit larger tires to see what wii clear the stays, fork crown and brakes.

nycbusi

Yeah. I figured i would need new wheels. I was hoping i might be able to adjust the brakes to make them a bit wider, but if i have to get some new ones so be it.

I am actually in to old bikes and honestly dont know what even to measure. any help is appreciated.

nycbusi

Thanks - i was hoping there was a bit of fork width sizing magic i might not know about. I'll bring it to the local bike shop and see what fits.

thanks

nycbusi

interesting... this is the exact rim i have.

29 x 2.25 tire on 700c rim- Mtbr.com

Im definitely not going that big, but this gives me hope for the rim at least. Now i have to see if something larger will fit the frame.

dabac

Look at front of bike, with current wheels installed. Look at the size of the air gap between fork legs and fork crown. How big does it appear to be?
The smallest number will be your guesstimate to how much bigger than current tire that will fit there.
Look at rear of bike. Air gap between tire and chainstays, seat stays, brake bridge and seat tube.
The smallest number will be your guesstimate to how much bigger than current tire that will fit there.

dsbrantjr

Check rear tire the clearance to the back of your front derailleur mechanism as well; it is the tight spot on two of my bikes

nycbusi

thanks guys - I will give a full measure after work today.

the internet really is amazing ... I found this link to the rim.....
https://www.randombikeparts.com/coll...k-aluminum-new

which shows the inner rim width at 14MM

then I found this: Tire Sizing Systems

[TABLE="class: grid"]
[TR]
[TH="colspan: 15"]Which tire fits safely on which rim?
[all dimensions in millimeters][/TH]
[/TR]
[TR]
[TH][/TH]
[TH="colspan: 14"]Tire width[/TH]
[/TR]
[TR]
[TH]Rim width
(interior)[/TH]
[TH]18[/TH]
[TH]20[/TH]
[TH]23[/TH]
[TH]25[/TH]
[TH]28[/TH]
[TH]32[/TH]
[TH]35[/TH]
[TH]37[/TH]
[TH]40[/TH]
[TH]44[/TH]
[TH]47[/TH]
[TH]50[/TH]
[TH]54[/TH]
[TH]57[/TH]
[/TR]
[TR]
[TH]13[/TH]
[TD="bgcolor: #11FF11"]X[/TD]
[TD="bgcolor: #11FF11"]X[/TD]
[TD="bgcolor: #11FF11"]X[/TD]
[TD="bgcolor: #11FF11"]X[/TD]
[TD="bgcolor: #FF1111"] [/TD]
[TD="bgcolor: #FF1111"] [/TD]
[TD="bgcolor: #FF1111"] [/TD]
[TD="bgcolor: #FF1111"] [/TD]
[TD="bgcolor: #FF1111"] [/TD]
[TD="bgcolor: #FF1111"] [/TD]
[TD="bgcolor: #FF1111"] [/TD]
[TD="bgcolor: #FF1111"] [/TD]
[TD="bgcolor: #FF1111"] [/TD]
[TD="bgcolor: #FF1111"] [/TD]
[/TR]
[TR]
[TH]15[/TH]
[TD="bgcolor: #FF1111"] [/TD]
[TD="bgcolor: #FF1111"] [/TD]
[TD="bgcolor: #11FF11"]X[/TD]
[TD="bgcolor: #11FF11"]X[/TD]
[TD="bgcolor: #11FF11"]X[/TD]
[TD="bgcolor: #11FF11"]X[/TD]
[TD="bgcolor: #FF1111"] [/TD]
[TD="bgcolor: #FF1111"] [/TD]
[TD="bgcolor: #FF1111"] [/TD]
[TD="bgcolor: #FF1111"] [/TD]
[TD="bgcolor: #FF1111"] [/TD]
[TD="bgcolor: #FF1111"] [/TD]
[TD="bgcolor: #FF1111"] [/TD]
[TD="bgcolor: #FF1111"] [/TD]
[/TR]
[TR]
[TH]17[/TH]
[TD="bgcolor: #FF1111"] [/TD]
[TD="bgcolor: #FF1111"] [/TD]
[TD="bgcolor: #FF1111"] [/TD]
[TD="bgcolor: #11FF11"]X[/TD]
[TD="bgcolor: #11FF11"]X[/TD]
[TD="bgcolor: #11FF11"]X[/TD]
[TD="bgcolor: #11FF11"]X[/TD]
[TD="bgcolor: #11FF11"]X[/TD]
[TD="bgcolor: #FF1111"] [/TD]
[TD="bgcolor: #FF1111"] [/TD]
[TD="bgcolor: #FF1111"] [/TD]
[TD="bgcolor: #FF1111"] [/TD]
[TD="bgcolor: #FF1111"] [/TD]
[TD="bgcolor: #FF1111"] [/TD]
[/TR]
[TR]
[TH]19[/TH]
[TD="bgcolor: #FF1111"] [/TD]
[TD="bgcolor: #FF1111"] [/TD]
[TD="bgcolor: #FF1111"] [/TD]
[TD="bgcolor: #FF1111"] [/TD]
[TD="bgcolor: #11FF11"]X[/TD]
[TD="bgcolor: #11FF11"]X[/TD]
[TD="bgcolor: #11FF11"]X[/TD]
[TD="bgcolor: #11FF11"]X[/TD]
[TD="bgcolor: #11FF11"]X[/TD]
[TD="bgcolor: #11FF11"]X[/TD]
[TD="bgcolor: #FF1111"] [/TD]
[TD="bgcolor: #FF1111"] [/TD]
[TD="bgcolor: #FF1111"] [/TD]
[TD="bgcolor: #FF1111"] [/TD]
[/TR]
[TR]
[TH]21[/TH]
[TD="bgcolor: #FF1111"] [/TD]
[TD="bgcolor: #FF1111"] [/TD]
[TD="bgcolor: #FF1111"] [/TD]
[TD="bgcolor: #FF1111"] [/TD]
[TD="bgcolor: #FF1111"] [/TD]
[TD="bgcolor: #FF1111"] [/TD]
[TD="bgcolor: #11FF11"]X[/TD]
[TD="bgcolor: #11FF11"]X[/TD]
[TD="bgcolor: #11FF11"]X[/TD]
[TD="bgcolor: #11FF11"]X[/TD]
[TD="bgcolor: #11FF11"]X[/TD]
[TD="bgcolor: #11FF11"]X[/TD]
[TD="bgcolor: #FF1111"] [/TD]
[TD="bgcolor: #FF1111"] [/TD]
[/TR]
[TR]
[TH]23[/TH]
[TD="bgcolor: #FF1111"] [/TD]
[TD="bgcolor: #FF1111"] [/TD]
[TD="bgcolor: #FF1111"] [/TD]
[TD="bgcolor: #FF1111"] [/TD]
[TD="bgcolor: #FF1111"] [/TD]
[TD="bgcolor: #FF1111"] [/TD]
[TD="bgcolor: #FF1111"] [/TD]
[TD="bgcolor: #FF1111"] [/TD]
[TD="bgcolor: #11FF11"]X[/TD]
[TD="bgcolor: #11FF11"]X[/TD]
[TD="bgcolor: #11FF11"]X[/TD]
[TD="bgcolor: #11FF11"]X[/TD]
[TD="bgcolor: #FF1111"] [/TD]
[TD="bgcolor: #FF1111"]
[/TD]
[/TR]
[TR]
[TH]25[/TH]
[TD="bgcolor: #FF1111"] [/TD]
[TD="bgcolor: #FF1111"] [/TD]
[TD="bgcolor: #FF1111"] [/TD]
[TD="bgcolor: #FF1111"] [/TD]
[TD="bgcolor: #FF1111"] [/TD]
[TD="bgcolor: #FF1111"] [/TD]
[TD="bgcolor: #FF1111"] [/TD]
[TD="bgcolor: #FF1111"] [/TD]
[TD="bgcolor: #FF1111"] [/TD]
[TD="bgcolor: #11FF11"]X[/TD]
[TD="bgcolor: #11FF11"]X[/TD]
[TD="bgcolor: #11FF11"]X[/TD]
[TD="bgcolor: #11FF11"]X[/TD]
[TD="bgcolor: #11FF11"]X[/TD]
[/TR]
[/TABLE]

so to be safe, from a rim perspective a 28/max 32 I can probably use [ assuming it clears everything ]

rm -rf

I use my hex wrenches to measure the space between the tire and the frame or fork. Measure the sides and the tops of the tires. A 5mm hex is 5mm between the flat sides, for instance. If you have 4mm on each side, you could probably add 4-5mm to your tire size. If the smallest gap is under the fork or at the brakes, add that gap minus at least 2-3 mm to your tire size.

Not all tires are true to size, some are a little bigger than their label says. So it's good to test fit the tires if possible.

And you need some leftover space on the top of the tread. On my old bike with only small gaps at the brakes, I rode over some newly repaved chip-and-seal with loose gravel dust and chips that was damp from rain. The tires picked up a coating, and I could hear it scraping the underside of the fork.

~~~~~
The tire chart posted above:

Those sizes are really conservative. The chart has been posted before, and many riders reported using tires well outside the approved range with no problems.

rm -rf

Your Jamis link shows a photo of the bike.

That's a typical road bike from a few years ago. The recent trend is to allow room for somewhat larger tires. On that bike, I'll be very surprised if you can go over 28c, and even those will likely be a very tight fit.

Riding on gravel

Rough gravel is much better with wide tires and low gears.

I have a Ti bike that can fit 40c (about 1.6 inch) tires, for the same conditions you mentioned. I recently rode it (no bags--just a day ride) on some hilly, rough gravel roads, and the 40c were barely enough for the loose gravel on the climbs. And I had a 30 front - 29 rear low gear. I had to get off and walk the grades over 10%. These roads had some recently added gravel, sized around 1/2 to 3/4 inch, and sitting loose on the road surface.

It's hard work riding on rough loose gravel. I was working as hard on 4% grades as I would on a paved road at 8-9%. At the low speeds on the climbs, narrow tires are harder to control and hold a line.

So I'd rethink using your road bike for difficult road conditions. For crushed rock rail trails, it would be fine, and for fairly flat gravel roads, acceptable, but you'd get beat up from the vibrations.

Touring

My Ti bike is for long day rides and also for credit card touring with a fairly light load. It has fenders and a rear rack. The fenders are really nice for heading out on a long day ride where there's a chance of rain or wet roads.

My front fork only has fittings for fenders, not a front rack. So all my load is in the back, which isn't good if I'm carrying a lot of stuff--it affects the handling.

blakcloud

You might be able to go 650b and fit a wider tire but that would preclude you purchasing new wheels, tires and long reach brakes and of course a lot of measuring. Research 650 conversions and there is plenty of info.

fietsbob

just go touring on it as is , you don't have to change anything to tour, you just have to Go some where ..
Touring is the activity.. bike touring is done on a bike ..

2 people shipped in their road bikes with a rear rack on it in advance.. last week They were rebuilt-up,

To take common-carrier public transportation here this week and have their bike ready to ride when they get here..




then buy another bike .. hard tail , rigid fork MTB from decades past. or new 26" like Surly 26" LHT..

N+1..

nycbusi

The trick is i want to make it to my destination in one piece and comfortably

riding it as is on Staten Island i pop my tire on these roads at least every 4x i go for a ride. I can just imagine what would happen on the roads in india

i am seriously contemplating buying a fuji that i saw on ebay in the mid $400s. im not in a position where i can spend too much.

nycbusi

thanks - the loose gravel i was describing was more like pebbles, stones in the road...

i cant see the pic for some reason you posted?

trailangel

Popping tires every 4 times out? What is your tire pressure?
If you want the bike for loose soil/sand, you need another bike IMO.

rm -rf

Oh, it's for a tour in India on a budget. Wow, that sounds great!

You might consider a 1990s rigid fork mountain bike. Specialized, Trek, and everyone else made bikes like these. Don't get a suspension fork, the rigid forks are way less maintenance.

I still have one of these Specialized Rockhoppers in the garage. They are bombproof, have a triple up front, click shifters, and take wide 26" tires. Easy to fix if something wears out or breaks. You can put 1.6 inch slicks or wider tires with minimal tread and be ready for any bad road you'll ride.



Check out this google image search "specialized rockhopper as a touring bike". A lot of examples! Some of these with front panniers may have a replacement fork, since I don't think the original fork had the bolt holes halfway down the blade for the front rack attachment.

trailangel

^^ I'll take it!

nycbusi

Yeh I m super pumped about the whole trip. We are 3 guys and a girl so far. One dude and one girl are Indian so we have local knowledge tht will be very helpful. ive been to india 5 times, but my hindi is crap and in the south they dont even speak hindi as their main language.

Like the previous guy stated... i dont think it is the right bike. maybe i mis-typed the loose soil... it is more like the road will be made of dirt, hard packed... or a paved road will have some dirt on it/sand. Not like i am riding through the sahara desert.

i have a 1957 Dutch bike in the pic below, i also have a 1940 Schwinn New World and i have a raleigh from the 70s. If i could i would prefer to use one of these bikes as my wife will kill me if i buy another bike.

nycbusi

sorry for the double post... I forgot to add that I took the Jamis to the bike shop and a 28 with a light tread schwable fit really nice on the front rim. It managed to fit on the back rim, but rubbed on the frame, so that was a no go. The 25 was just too thin. Hence the above post for the search.