SoreFeet

I heard that the later year models don't take as wide of tires. I'm running 23C tires now and it looks like the front would take a 28...but the rear, I think the brake caliper might get in the way.

I believe mine is a 1988 model with the tri color group, Avenir Equipped whatever that means. It is the grey spatter color scheme.

I think 25 will be the limit, but we'll see. I am running Serfas SECA 23's...one of them appears much wider and taller than the other even though they are the same size.

ThermionicScott 

Allen wrenches make good feeler gauges to guesstimate how much more room you have for tires...

canklecat

Just eyeballing the two sets of 700x23 tires (Vittoria Zaffiros, Schwalbe 1's) I've had on my '89 Ironman Expert with original Araya CTL-370 rims, I'm betting 700x25 is the largest it'll accept unless someone makes a set of 700x28s that run smaller than spec.

FWIW, the Schwalbe 1 V-Guards are nice. Relatively comfortable but not sluggish at around 90-100 psi on chipseal, striated concrete and rough pavement. Much nicer than the Vittoria Zaffiros, which felt like riding on steel rails at 120 psi and felt sluggish and slow at 90.

So maybe the right set of 700x25 tires would work about as well as 700x28.

RobbieTunes

I run 25's in clincher 24's in tubular.
Never have gotten any 28's to work.

TireLever-07

I had a 1986 Centurion Elite RS. These were cheaper than the Ironman family. It was OK with 25MM wide tires on it. I found it at a garage sale. Looks like it was lightly used. Might have bought it with 23MM, skin walls. (Those might have been the original tires) So I rode over a broken beer bottle hidden in a pile of leaves, near my house. I put a 28MM spare tire I had at home. Later riding it, I hit one patch of wet leaves, locked up the rear, lucky it kept going straight. I gave it a modern real derailler & replaced the Bio Pace chain rings with steel, 39T & 52T teeth. Was a good climbing bike.
We have one(at least) hardcore Iron man lover here. Cheers

SoreFeet

LOL thanks guys...Funny I just got a set of Vittoria Zaffiro these are the new compound with G...graphene whatever...

Anways...The 23C seems to be really narrow yet the 25C tire seems much wider. They don't seem to ride harsh at all. I think the new Zaffiro is sort of a midrange tire.

I almost bought a set of CX Corsa tires...but i got the Zaffiros for 12$ a tire.

noglider 

What a good idea. I'm going to do that.

smoothness 

i'm pretty positive that i have 28c gatorskins on mavic open 4 CD and they fit both front and back. i have the unicrown fork.

bluehills3149

I'm running 28's on mine. "Bontranger Race All weather". Plenty of room front and back.

ThermionicScott 

I read about it here on BF!

canklecat

Yeah, the Zaffiros are good values. They don't ride badly on smooth pavement at higher pressure. Some of my fastest Strava segments were on the Zaffiros back in June when I first got the Ironman. But those were at high pressure on smooth pavement.

I have chronic neck pain from an old injury so I'm probably hypersensitive to jittery tires. The Zaffiros weren't awful at lower pressure, and not too bad on gravel. Just a bit sluggish. The Schwalbe One V-Guards are far better but I snagged a pair for $15 each from Jenson. At the usual full price for Schwalbe Ones they aren't such a bargain -- for what they usually cost they'd better be good!

evets11

I managed to "Shoehorn" a 28mm Conti Gatorskin under the rear brake bridge just BARELY clearing the brake bridge, with clearance about 0.5mm at the highest tire hop and 1.5 mm clearance at lowest hop, averaging 1mm clearance at 110 psi. I sanded off the paint under the brake bridge where the tire lines up about 15mm wide but didn't file into the metal. I don't pump the tire past 110 psi even though max pressure is 120 psi fearing it'll expand the tire so it rubs on the brake bridge. I suppose if you're an expert wheelbuilder and can tru roundout PERFECT the clearance should be uniform 1mm under rear brake bridge provided the tire's Perfectly Round w/o hops. The Best I can tru a used wheel's roundout is within 1.0mm. I had to fabricate an alloy "angled wedge washer" with a file to angle the Suntour GPX Brake up so it clears the brake briige. I just unbolted the brake mounting nut, slid the brake out and added the 'wedge washer" on next to the washer that's next to the brake bridge. That "lifted" the brake a couple mms so it cleared the tire. Before that I 1st had to file flush a small rounded bulge that hung down under the brake pivot hole on the frame's brake bridge, and a tiny bit of alloy off the underside of the GPX brake at where the pivot bolt bolted to the brake bridge so the 28mm tire would not rub. NONE of this caused ANY significant structural weakness. I think maybe you might only have
to do this 'Hack' with the brakes with the Suntour GPX Brakes. Luckily after doing this Hack there was still enough sliding room in the caliper arm slots so the brake pads lined up to the rim ok. I have the '89 Expert Model with Suntour GPX Gruppo and their brakes bulge wider around the brake pivot bolt so it hangs a couple mms below the brake bridge. I've been luckly Never to have my tire cling onto any road tar/debris or get a sliver caught in it. I imagine if so and it gets caught under the brake bridge it would either scrape off, rub, cause a puncture, or worse case the rear wheel would skid. I live in the Desert, all flatland, no hills, so I'll take my chances with possibly the rear wheel locking up since I rarely ride over 25 mph, averaging 17-20 mph cruising. I've ridden this bike several hundred miles with 28mm tires without issue. I haven't tried but I have 3 different ideas to add some more rear tire clearance, say 0.5 -1.5 mm more. Maybe a combo of Ideas # 1/2 or 1/3 can provide up to 2.0mm - 3.0mm total clearance: Idea #1 - Carefully clamp the metal under the brake bridge, using a rounded carved out piece of wood on top and bolted together roll of quarters underneath (same diameter as 28mm tire), and using a C-clamp, clamp together to flatten the metal under brake bridge a little, say 0.5-1.0mm. Keep the brake on as u do this so as the brake pivot hole in frame doesn't get squished. Idea #2 - with a 10mm round file (same diameter as rear axle) file say 0.5-1.0mm off of bottom of both rear dropouts directly under where the axle rests in the dropout. This has to be lined up PRECISLY on both dropouts so as the wheel sits PERFECTLY centered btw. the chainstays. Then fabricate a couple metal shims to slide on top of the axle and make them wide enough that the QR keeps them clamped in place. Carry a couple spare shims hidden under the bar tape jic. Idea #3 - File the threads flat on portion of both sides of rear axle flush with where threads start on axle. This has to be positioned precisely on both sides of rear axle so as it is perfectly flat both sides therefore lowering the axle about 0.5 - 1.0mm. This Should NOT weaken the axle as long as you don't file into the axle, just file off the threading. Keep in mind if you do Idea #2 or #3, as you file more metal off, put the wheel back into the dropouts and TEST that there's STILL Enough "Grab on the Dropout" on the top of both sides of QR Nuts! Make same shims as in idea #2 and carry spare shims too jic. The Rear Brake Bridge is the ONLY clearance issue with 28mm tires on this bike. There's LOADS of clearance btw. seatstays and chainstays and 3-4 mm under the fork crown and 4-5 mm btw. both fork blades with front 28mm Conti Gatorskin tire. Being a Clyde at 225 lbs I HAVE to have a 28mm Rear Tire MINIMUM. That rear brake bridge REALLY is a screwed up design flaw to an otherwise PERFECT Frame. It should have been brazed in 2-3mm higher. The Geometry of the Ironman Frame along with the Tange #1 Tubing provides a NICE Ride. The Centurion Ironman Dave Scott Bikes are Beautifully Engineered Machines!

RobbieTunes

See? Anything is possible in Ironman Empire.

noglider 

Was that legible?

RobbieTunes

I have some tubeless HED Ardennes that are 22mm wide inner. 700x28 may fit in there on them.
I've never gotten 28's to work. The problem is definitely the rear brake caliper, and then the bridge.
So I "imagine" I'm on 28's and pretty soon, it all goes away.

canklecat

I get what evets11 is saying. The main thing in the way of larger tires on my Ironman Expert is the Suntour GPX rear brake. I could file it down or replace it with brakes that offer a bit more clearance.

There appears to be enough room for 28's on the fork with the GPX brake, and on the rear between the chainstays. It's only the GPX rear brake bridge that makes larger tires a tight squeeze.

I haven't gone the route of filing down the rear brake bridge yet to accommodate 700x28 because I'm pretty satisfied with the 700x25 and latex tubes I've been using. Much nicer feel on rough chipseal.

However even the Continental GP Classic (700x25 only) has a raised center tread ridge that lightly scrapes the rear brake bridge at first but fits better as the tire wears a bit. The Ultra Sport II in 700x25 cleared, no problem, but the GP Classic is a nicer tire for not a whole lot of money.

RobbieTunes

I don't think legible is necessary.
Like legislation.

Chinghis

I liked a comment from 2017 above, because I have been able to fit some Bontrager 28s on my Ironman. But yeah, on the rear, I had to kind of push it past the pads. Next time I'll just deflate it a bit. It's very narrow clearance, but so far it has worked.

When I got it, it had 20s on it. Really fast, but I hadn't been on anything that narrow in years. (I generally ride 1.5" slicks on an old mountain bike.)

Mr. 66

I would get a different bike that actually can use the tire size I want to use.

RobbieTunes

“The horror, the horror.” ... (With these final utterances, Kurtz at last accepts the evil present in his soul and welcomes the promise of some semblance of peace in death.)



It's an Ironman.

evets11

This is my 2nd post ... a follow up: I added another 1.0 mm of tire clearance under the rear brake bridge by filing flat sections from an equal amount of threads from both sides of the rear axle, but no metal from the actual axle so as to weaken the axle. I fabricated a couple shims about 1.25mm thick to shove into the space btw. the top of both sides of the axle and dropouts. It's a bit of a PITA to install the rear wheel now, necessitating flipping the bike upside down resting it on saddle and handlebar hoods, removing the axle skewer, sliding the axle in so the filed flat sections of axle threads rest on bottom of dropouts, then shoving in the 1.25mm x 8mm x 5mm shims (made from folded wall of beer can) btw. top of axle and top of dropouts, making sure both sides of axle rests against adjustable dropout stops so as tire is centered btw chainstays, then reinstalling skewer and cinching it down. Removing both cone shaped skewer springs and doing without them makes this easier. Carrying a couple spare shims comes in handy for roadside flat repair jic you lose the shims. As long as the shims are a tiny bit wider than the width of the dropouts they hold nicely in place crimped in by the skewer 'nuts' and the wheel stays snugly in place as long as the Skewer is cinched down 'tight enough', not 'Super tight' to whereas you can break the skewer. Now I have 1.75mm clearance at the highest hop of the tire and 2.25mm at the lowest hop of tire. I retrued the rear wheel the best I could to w/i ~0.25mm lateraly and 0.66mm roundly, dished w/i 0.5mm, and tensioned the spokes with nearly equal tension "26-27" throughout all the drive side spokes and "19-22" throughout all the non drive side spokes with a Park Tool TM-1 Spoke Tension Meter (with 2.0mm straight guage spokes). That's about the LIMITS of my Wheelbuilding abilities, I'm guessing about a B+ to maybe A- if a Pro Wheelbuiler would grade it, but pretty damn good overall! So to Recap, in order to 'shoehorn' a 28mm Continental Gatorskin Tire onto the Rear of a 1989 Centurion Ironman Expert with Suntour GPX Brakes requires SEVERAL Hacks: Removing the Brake and Filing about 1.5mm off the round underhang of the Welded 'Flat Round Washer' that hangs lower than the frame's brake bridge and filing an additional ~ 1/2mm from under the brake bridge of frame itself. Then fabricating a V shaped wedge washer ~ 0.5mm thickness on top and 2mm thickness below and insert btw where brake bolts to the frame's brake bridge so as to angle up the brake so it clears the tire. Then after tightening the brake mounting bolt figure out how much of the 'bulge' of the brake that encircles the pivot bolt that hangs below the brake bridge you need to file so it's level with the brake bridge, then file that down so it's flush with the bottom if the frame's brake bridge. This should give you ~1mm of tire clearance under the brake bridge at this point. Lastly file both sides of the axle threads flat right to the top of the Hub axle but not ONTO the axle on sections on exact same location of both sides of the axle as I described above and fabricate and install the axle shims as I described above. Doing ALL these hacks SHOULD give you an avg. of 2mm of tire clearance, 2mm Exactly if the wheel/tire is Perfectly round. I've put about another 100 miles on the bike since this latest hack of filing the axle threads down and the wheel stays very snug and secure w/o issues. If you Don't have GPX brakes I imaging no need to file any alloy from your brakes. You may Not have to fabricate a V shaped wedge shim washer either. I would have preferred 3mm of tire clearance per what's recommended but better it be 1mm less clearance under on the rear tire than the front. I most probably will never get large enough debris lodged in there that will cause wheel lock up anyway. One last thing: I was in Error on my 1st Post ... you Cannot 'crimp' the brake bridge to give more clearance. The welded in hollow hole through the frame's brake bridge that the brake pivot bolt slides through is flush with the bottom of the frame's brake bridge so it won't budge. With these old steel frames you can usually tweek them to accommodate modern luxuries if you use ingenuity thinking outside the box. These are pretty cool Hacks I came up with and they WORK Really Well!

RobbieTunes

I read the post thoroughly.
A headache. A nosebleed.
Then Bravo!

Ironman.
Adapt.
Overcome.
Ironman.