Pedal strike is a more serious problem with a fixed gear. You cannot coast through the corners and if you do hit your pedal on the ground, one or both wheels will be off the ground at least for a little while. Could be a problem!

If you're worried, get shorter crank arms.

So doing my due diligence for the elusive right frame/bike there are moments that just take your breath away....

Pedal strike is a problem if the rider panics when it happens. Pre-priming panic is a very bad idea.

The strike lasts what --0.01 second? We're talking about the bottom 2 degrees of crank rotation while the crank is moving at 100rpm. The bike does not have time to get off the ground. Neither is the bike a perfectly rigid system. And it is not like the crank buries itself a centimeter in the pavement, creating a new little pothole. All that happens is 1 millimeter of pedal scrapes for a moment.

The old test for low bottom bracket was to walk the bike around a bit and if the toeclips clattered on the ground a lot that was a nice low bike. The toeclip clatter is much worse with fixed gear. The flip side is low BB gets you through corners much faster. Yes, you must keep your inside pedal up, still that corner is way faster. The entire bike is more aero, just plain closer to the ground. Going from a high bike to a low bike the change in drafting is quite dramatic. Not only do you get a better draft off everyone, in a race situation you are denying draft to followers. No one will ever know any of this unless they ride old bikes. Real old bikes. Bikes with 9 and 10cm frame drop. Absolute conformity is the order of the day now and these bikes will not be built again. Even custom builders would be mostly unwilling. Absolute conformity enforced by errant nonsense and lots of screaming about non-existent danger danger is why I am old and grouchy.

I have a 25" Bridgestone 400 ('84 or '85) that I intend to convert. I've measured and it for sure has clearance for 42's, and may even be able to squeeze in larger (with no fenders). Bottom bracket drop isn't ideal, as it originally had 27" wheels (I want to say it's around 270mm to the ground with 27x1 1/4 paselas). With the 27" wheels I have on their now brakes with 49mm reach just reach. So, 23mm more reach only puts it at 72mm reach for the brakes.

This!

A low speed swerve in traffic can easily launch a 200 lb rider flying over the bars. Don't ask how I know.

Oh, man!

I kinda want that for my signature.

I have a 198(5?) Nishiki Sport that fits 650Bx42 front and back with fenders no problem. It's a low-end frame, but I like it enough. It has more appropriately sized fenders (and matching tires!) now.

Rudi

If you want it you may certainly have it.

The Ideale 53 is seeing lots of miles and is wonderful. And perfect for the bike.

hat and beard

That low end frame shows a lot of quality details. Generally I'd discourage conversions, yours was begging to be done. All looks very right.

Just a word on what I've ended up with. I found this online up for auction and the more I looked at it the more I liked. It's a Trek 750 Multitrack and it's a complete bike so other than changing brake pads, tires, and my on all bikes bike saddle and cleaning/servicing of parts it's ready to ride (may want to change to a drop bar as this will be primarily a road bike). So what were the likes? It appears to be in good condition, all Chrome-molly frame/fork with lugged frame, not the lightest but not the heaviest at around 25lbs per catalog, pannier brazeons in the fork tube, two sets of water bottles brazeons and a true Swiss Army knife of a bike. I've got a spare pair of fenders I hope will fit and a set of 32mm tires. When I get it all set up and have a ride or two I'll post the build and what it was like. No, didn't get to 650B size wheels, these are 700c, but it came spec'ed with 38mm tires which would be wider than anything I've ridden since my balloon tire Schwinn Corvette 3-speed 5 decades ago.
So thanks for your thoughts and encouragement, looking forward to the ride.

700x38's should give you a nice plump ride, but get some higher quality tires, else it'll negate the comfort and performance effects of wider tires.

Gugie the 32mm tires are Compass light sidewall Stampede Pass. I have them on our Stevenson Custom Tandem and on my Katakura-Silk/Nishiki-Professional and the ride is sublime in both cases though with more air pressure with the tandem! Since I have these on hand and they've worked so well for me so far I will wear them out first before exploring larger 34mm-38mm tires, but I agree the quality of the tire is critical to the ride/performance of any tire wide or narrow. Wide, heavy and stiff tires can't be corrected much even by the best steel frame/fork.

P.S. I also thought $70.00 for this bike was a pretty good deal and its in my size. Wow that just caught my thoughts, $70.00 is what you can pay for a single quality bike tire nowdays, let alone a complete working bike, vintage the best deal in biking I think.

Good choice - that's a solid bike that will allow for many different types of set-ups and experimentation.

I modified a similar vintage 720 Multi track into a drop bar bike with bar end shifters. However, the bike never quite felt like it fit me after I added the drop bars - too jammed up. I experimented with different length stems but never got it to where I wanted it. When looking down at the front wheel I could see the front axle with a couple inches to spare and I think this is an indication that the frame was simply too small for what I tried to do with it. It was my first attempt at a restoration/modification. I eventually just took off all the new gear and put it back together in its original hybrid form. But - that's how we all learn!

There are several previous threads on BF with good advice re: drop bar conversion if you are interested.

Good luck and post photos as you progress.

jlaw

Thanks jlaw will post just making up components in my odds and ends will be fun to see how it all ends up and will post when done with before/after of changes though in a new post of the restored bike.