Podolak

Apologies if this is the wrong place to post this question, here is my story and I can move it to a different sub-forum if requested.

I have a 2006 Marin Novato (fully rigid 26" mountain bike marketted as a commuter). It has sentimental value and I do not want to replace it with a new bike. However, I am extremely curious about making it into a 69er. I'd like to replace the front fork with a 29er fork (maybe Surly ECR) and disc brakes. I'd go disc brakes in the back as well, its rim brake front and back. The 26" steel fork it currently has is rim brake only so it has to go regardless.

What types of things should I look for when doing this. I assume I can't just buy a fork and wheel and go to town, there must be measurements and so forth to consider.

Any help would be appreciated.

Podolak

Finally found a pic (Its currently in NY and I am in MD).

hybridbkrdr

I built several bicycles and modified a couple. For whatever reason, I can't think too much from the top of my head right now but I'd say things to look for: is your fork compatible more with an integrated headset and is it for a straight tube or tapered. Also, what kind of hub is compatible with the fork (9mm QR or thru-axle).

By the way, that looks like a very nice bike. You could always upgrade to Alivio V-brakes and Jagwire brake pads if you're not satisfied with your braking.

Why not go 27.5" at the front? You also have to pay attention to crown to axle length of the fork.

Happy Feet

Right off the hop, a 29 suspension fork on a rigid 26" frame is going to throw the geometry off by quite a bit and really effect handling. One of the big effects will be a loss of control when climbing. The bike will want to lift the front end off the ground and become quite twitchy because your center of gravity (COG) will be more rearward.

For brakes. Replacing the front V fork to disc is easy if you want. The rear, a little harder as you don't have the mounts. But, one great improvement you can make is going with compressionless brake housings for your V brakes. Shimano and Jagwire both make them.

On this bike I just went through that compressionless housing process, as well as upgrading the U brake/cantis to more modern bmx style cross brakes and V's up front. The effect on braking was pronounced. I can actually stop now on steep mtb routes.




I've replaced a 26 rigid fork with a similar 26 suspension fork before and even there, the height difference made this twitchy effect while climbing quite noticable. But in other respects it worked fine and I like it for mtbing.

This first pic was the first conversion using an old hybrid suntour suspension fork. I put a lot of gravel road/mtbing miles on that thing and really liked it as a cheap, low travel fork.





This pic shows the second, better Marzocchi suspension fork. It has both rim and disc mounts so, if I wanted to, I could go 180 rotors, hydraulic disc but it stops fine with V's and compressionless housings.

guy153

It looks like the wheels might just fit but you wouldn't be able to use super fat tyres.

The biggest problem I think is how to mount the rear disk caliper? Unless you want to weld something onto the frame but if you do it needs a heat treatment.

If you go with rim brakes on the rear I doubt they would fit as the V brake posts will be in the wrong place relative to the rim.

I heard 26" wheels are coming back into style anyway so I would keep it original. It looks like a nice bike!

hsuBM

First, rent a disc 29er for a week and ride it for at least 200 miles in at least one downpour and see if you actually feel any significant difference worth spending ~60% the cost of a whole new bike on some wheels, brakes, and a fork & starnut.

Next: Research “rake & trail”

If it seems straight forward and dead easy, go forth and continue your mod quest.

———

If you do the mod, you’ll end up with a raised BB, a slacked out steerer, and since geo specs on even mid-end bikes are less than reliable, you’ll just be WAGing your trail or (spending 100-150% as much as you would on a new bike) experimenting with different forks to find an amount of trail that you dislike the least.

———

That looks like a sweet bike. It’s cool that it has non-flatmount style disc mounts, though I haven’t seen any bikes with those in like eight years. Getting a new caliper to fit might be a challenge. Planned obsolescence is one of many reasons I just stick with rim brakes on most of my bikes. Compressionless housing and good pads are better than fine for everything that isn’t hucking it down some insane MOAB or 14er cliffsides.

Only thing I would change are the tires (because I like tires that roll fast and get lots of flats) and the bottle cage (King Iris).

ofajen

First things first. Why do you want to do this? That is, for what riding purpose? It will inevitably be a lot of time, trouble and expense to do all this, so you probably want some clarity on what you are after and why. And if you are after something profoundly different from what that bike was designed for, it will probably be much more efficient to get a bike designed for that purpose.

Otto

Podolak

Wow, amazing input and so much of it. Major appreciation all.

I have moved to a new area and sold off most of my stable. I was planning on keeping my Kona Dew Drop only, disc brake 700x38 marathon plus tires, etc. However the trails got a bit rough when the rain hit. I realized I needed something with a bit wider tire for when the mud and wet rock come in. I hadn't sold the Novato yet mainly because I was keeping it as something to use in NY until I fully vacated and also because I took it through several winters and honestly not sure I feel comfortable selling it. My theory was keeping a frame I have sentimental attachment to and bringing it up to speed for a slightly more rugged environment than I anticipated.

The theory behind a 29" front wheel was to help with traction and handling a bit. The disc brake idea is for stopping power, the frame was built for disc brakes just not the fork. I am open to suggestions even ones such as this is a terrible idea. Again all of the input is very appreciated.

Podolak

ofajen

You might find that the 26er does fine with the right tires. I have an old 26er MTB that I ride a lot and have two wheel sets: one with smooth, fast tires for dry (or at least paved) surfaces and a second one with wide, small knob tires for wet wintry mess.

The knobby tires are Continental Race King Protection 26x2.2. As wide as the frame can handle and they clear mud well, roll fast and grip on sloppy trails. If you switched to 29er on that frame, you would probably not be able to run as wide a tire as you can with 26ers. Food for thought...

Otto

Rolla

The thought of jacking up the geometry, buying a full disc brake set-up (levers, calipers, rotors), and having to carry two different tube sizes would talk me out of the whole thing in about a minute. As it sits, you've got a perfectly nice all-weather commuter; it ain't broke, so don't fix it! Besides, adding a few millimeters of tire width isn't going to turn either of your bikes into a mountain bike. If you're going to regularly tackle wet, muddy, and rocky trails, get something made for it.

Podolak

Rolla

I don't disagree. I think I'm decidedly not going to make a 69er. I'll have to give disc brakes more thought. I'm trying to not +1 my stable though.

Rolla

Ah. In that case, just let the Dew Drop tackle the job. It's already got discs, and a different tire choice might work better for you. FWIW, a Jones bar or something similar might improve the off-road handling.

Happy Feet

No, the obvious solution is not to do it unless there is a compelling reason.
I think we have all seen your franken bike and most would not want to go down that route.

wolfchild

A forward bent seat post sounds like a terrible idea.... A shorter stem or a 30 degree raise stem plus regular seat post with saddle adjusted slightly forward is all that is needed.

veganbikes

I would stick with 26". If you like Disc brakes which can be quite nice you can find forks that will accommodate or have someone build one which there are plenty of excellent builders in the U.S. who can do it. 26" is a fine size and while a mullet sounds like a good idea in practice they never really looked good. If you are going to have a party have a party and if you are all business be all business but trying to mix the two just never really worked well no matter what people said in the 80s

Podolak

Ya'll gave some really good input and it is greatly appreciated thank you!

Happy Feet

Just to confirm. This is the bike you are talking about?

Or this bike?