Onza T-Pro build thread

[thousandwords]

I thought I would do some thing new- I have never documented builds for any of my previous bikes but being brand new to trials it will probably help me a lot keeping my thoughts organized and in one place.

I started a thread recently on the Beginner Chat introducing myself and the new old stock Onza T-Pro frame I recently purchased online.

 

Well frame arrived this morning, so today is officially day one of the build!

 

This will be a slow build, stretched over weeks, with frequent and long interruptions. For one, I am still learning about this so I might take a while to figure out or decide what way to go for a certain part. Furthermore I expect I might even make mistakes, going to the wrong part, and having to reconsider and readjust- further delays. Lastly, even when lucky enough to order correct parts, I will order mostly from Europe online sellers (mainly Tarty) and it might take a bit longer for the parcels to get to this side of the pond.

 

The idea is to add small updates as they happen (new parts coming in and being installed, etc.

As such, it will be boring stuff for the majority of people here, but I feel I would enjoy documenting each step of the build, from planning phase to completion.

And if even one single person here would find pleasure in following, that would double my satisfaction.

So here we go!

[thousandwords]

THE FRAME

 

Once frame is in my hands I was able to figure out a few important specs I needed before ordering certain parts.

1. Digital caliper out- rear hub spacing 116 mm as Ali hinted on my introductory thread. Now I can order a rear hub. (In all honesty digital caliper said 113 mm but I have faith 116 rear hub will work fine).

2. Spare English thread bottom bracket cups smoothly going in. Now I can order correct bottom bracket.

3. Head tube designed around straight 1-18" steerer (again, just as Ali predicted), integrated headset, looks like zs44 (digital caliper showing 43.8 mm top and bottom inside diameter for the integrated "cups". So now I can order headset and fork.

 

So far not a bad first day.

But of course it would have been to easy if everything worked out just as nice, so enter rear brakes.

[thousandwords]

REAR BRAKE

 

One of the countless pieces of information of enormous importance regarding the frame that contributors to my introductory thread helped my understand is that it features Magura HS33 mounts (which at the time was a novelty for me).

As such, even before frame came, I ordered the HS33 brake, brand new but without lever, from a private ebay seller. Brakes came a few days ago, but without a frame there was not much I could do with them.

However, once frame showed up this morning, it was time to spring into action and proudly install the first part on the new frame! I could not wait to do it.

Now, I am the type that before reading instructions, tries to figure out the inner workings of new contraptions, just as an exercise in problem solving, and also from pure curiosity. If I stall and get lost, I will open the manual, but I love trying to figure it out first without much help.

So out comes the brake, with its several pieces, and I give it a go.

 

I cannot remember being so utterly confused in a very long time. Nothing made any sense. Nothing seemed to fit.

I tried a few different approaches.

Took the calipers out of the clamps just to make it easier, and focused on the clamps themselves going onto the frame. Nope.

Forgot the clamps for a second and tried to figure out the way the booster clamps go in. No chance.

It was like fitting square pegs in round holes. I bet it made for good comedy if anybody was around. Luckily nobody was.

 

It took me a few tries but eventually I figured out that either something is wrong or too complicated- either way I needed some actual research, so went on the internets for guidance.

I quickly learned 2 things.

1. The brakes came with the Evo 2 adapters. No wonder I was scratching my head trying to figure out how the clamps fit on the mounts.

2. The included brake booster and the other bracket were the smaller spacing needed for front brakes. Once again, no wonder they gave me headaches while trying to fit them somehow on the frame mounts.

The private ebay seller did not include much in the way of specs and I know so little about this that it took me a while to figure out all this.

Well digital calipers out again, frame mount spacing 102 mm, so I need to order a new brake booster that fits that spacing.

What bother me a little is that I am not sure I can order the other bracket in the new spacing, I have to do more digging on that.

 

So after some head scratching, back on track.

 

Luckily, after getting the frame and started researching what I need to order, I noticed that most complete hydraulic rim brakes do not come with clamps, so I already ordered those, coming from Europe so don't have them yet but should be here soon.

[thousandwords]

In terms of functional steps, all the above is everything that could be done with what I presently have.

As there will be a lot of waiting for parts to come, so frame will be collecting dust in the meantime, I decided to take advantage and customize the look it by painting a few small parts of the frame.

Making it my own, so to speak.

Picked head tube, seat tube, bottom bracket, bash plate mounts, rear brake mounts, and a portion of the chain stays.

Will use some metallic paint (bronze, brass copper) that I have bought for another project which is on stand by for now.

Masked the majority of the frame with painter/masking tape and applied a coat of metal primer.

Will let primer cure overnight, tomorrow will start applying paint.

Once paint complete will actually post pictures.

[thousandwords]

That's it for day 1.

Maybe not much, but I'm happy.

[thousandwords]

Now a thought or two for the direction I would like to go next.

[thousandwords]

WHEELS.

 

Well now I know hub spacing so I am ready to order hubs, rims, spokes and build wheels.

 

I am very tempted to try something a bit unusual.

"Mullet".

19" rear, 24" front.

What got me thinking about it is the fact that a whole bunch of 20" forks are sold out with a few online sellers. There are a couple of forks available, but not many. @4" though seem to be plentiful.

Then, once I started pondering about it, I thought to myself that maybe a slightly larger front wheel might make learning trials and riding the bike, less "alien", which was one thing that stuck with me form my introductory thread.

Haven't made final decision, but chances are I will go for it.

[thousandwords]

BOTTOM BRACKET

 

So as of this morning I know it's English thread, so let's order one, right?

But.

I have built a number of bikes using Campagnolo Ultratorque, Campagnolo Supertorque, SRAM GXP, Shimano Hollowtech, and some less common 30 mm standards.

All of them have the spindle integrated in the cranks, not the bottom bracket.

The only exception is a vintage time trial bike that asked for square taper bottom bracket simply because the cranks and chainring I wanted to use were using that standard.

Generally speaking, road and mountain bikes, from what I can tell have walked away in large extent from bottom bracket standards with integrated spindle (ISIS/splined, square taper) if not for other reason, for weight saving.

And because of that, once you build almost all your bikes that way, you start perceiving square taper as antiquated and heavy. Cheap and outdated.

 

However, browsing available bottom brackets on trial specific websites, I was struck by how many ISIS and JIS bottom brackets are offered. The majority.

It made me wonder why, and it made me think I perhaps should not stray away from it.

 

Maybe because of the nature of trials, cranks get bashed a lot and it's a lot cheaper to buy a new set of cranks than a crankset of a standard that includes the spindle in the cranks. Just my speculation. Whatever the reason, the more I think about it, the more I think I should go the heavy and outdated way.

Hm.

 

[DYAKOV]

Dude all I can say is you’ve picked the right nickname! 

[thousandwords]

DAY 2

 

 

Frame painting time

[thousandwords]

Ordered fork.

24" so yup, will give mullet a try. Worse come to worse I can later get a 20" fork.

[thousandwords]

DAY 3

 

First batch of parts came. Took about 10 days to cross pond. Before I knew any actual specs of the frame I could only order some universal parts that would fit any bike regardless of various standards.

Sn now I have

 

-stem (Bonz, 150 mm)

-handlebars (Comas, 105 mm rise).

 

Both sizes were shots int he dark, I really don't know what is optimal, but I had to start somewhere.

 

-chain tensioners: ordered  both the snail cams (Comas) and the chain tugs because would like to play with both just to see how well each works.

Unfortunately the snail cam bolts I ordered are the wrong ones because I id not pay attention- it says in the description they are M6 as opposed to the M5 that most frames require- I just assumed these things are universal.

So for now having the tugs as an option is great.

 

-brake clamps- Echo. Once frame is fully painted I can install the Magura HS33 calipers onto the frame

 

[thousandwords]

DAY 4

 

Ordered bottom bracket (splined, 128 mm wide), cranks, freewheel (18 teeth). Bashring is included with the cranks but being a beginner I won't need it much for quite a while.

[thousandwords]

DAY 5

 

Well this is actually not something I've done in one day, it's been ongoing while I wait for parts to come or for myself to figure out what to order and then wait for that to come. Makes me feel like I am doing something while I wait.

 

Frame painting is almost done.

It would have been fully done a few days ago but I ran out of primer exactly when I was priming the very last stretch, the bottom half of the down tube, which will be painted in metallic copper.

So I ordered new primer (and some extra clear coat and a shimmering yellow for the small downtube and top tube bits where Onza put their stickers on), now waiting for all of that to come so I can finish the paint.

[thousandwords]

Package form Tarty came (I cannot believe how fast it came, was expecting it in another week or so).

Cranks, front freewheel, bottom bracket.

 

Down tube not fully painted but I could not resist, had to test everything for fitting, especially that I was worried that the 128 mm BB will be to narrow and it might not clear the chainstays.

 

First of all, I could not believe how tight the ISIS spline tolerances are, the crank arms needed a lit of coaxing to engage the BB splines deep enough to allow the bolts to catch the BB axle threads, and once that happened, threading the bolts into the axle took more effort than I remember being needed for the other splined BB I used in the past. Build a few bikes using SRAM GXP and proprietary White Industries BB, all splined, and putting everything together is a breeze. Not with ISIS I guess, but it did get in.

 

To my relief, the cranks cleared the chainstays.

To my annoyance, I initially thought they cleared them too much, and started worrying about chain line. I was in fact ready to order a second, narrower BB (was thinking 108 mm). However, one gentle soul on this forum (aener- thank you again!) pointed out that the extra clearance is good and might be needed to clear the HS33 calipers, and that chainline will be fine. Once I read that I put calipers on, and lo and behold, 128 mm actually felt really good choice.

 

I will probably leave everything on now that it's on, and deal with the extra tape masking for the last painting day.

 

Also now that the brake calipers are on I feel the urge of buying the correct brake booster- the one that came with the brake was for fork.

 

[thousandwords]

Fork is probably one or two days away from being delivered so starting thinking about headset.

 

This is a bit of a mystery for now- I have never seen such a headset before on any bike I have built before.

 

The head tube is milled internally at 45 degrees as all integrated head tubes are. But the only integrated headset standards I know ask for 41.8 or maybe 42 mm outside diameter for the bearings.

This head tube has an internal diameter of almost 44 mm. If you ignore the 45 degree milling you would automatically think internal cups/zero stack headset, those are 44 mm amongst other sizes.

But then all zero stack/internal cups headtubes I've seen are straight inside, not milled as if for a bearing.

 

For now I will wait for the fork to come (will be here shortly) and use the 2 spare 41.8/42 mm bearings I have laying around to see how that looks like, I am pretty convinced it will work poorly as I will be back at square one trying to figure this out.

I will also start a separate thread dedicated just to this issue, in hope many more people might see that one, rather than these lines buried deep into this already stuffy thread.

 

Just in case anybody is curious, I included a couple of pictures= sorry for the upside down caliper reading.

 

[thousandwords]

Finally, ordered parts for rear wheel build- rim, hub, spokes, sprocket (12 teeth).

One mention about the sprocket- teeth are all the way over the outside edge, so the chainline should be a bit better that way as compared with if it was midline. Makes me feel aven better about that 128 mm BB.

 

Will not order front wheel stuff for now as I need to decide whether I want to put a 20" or a 24" wheel in that 24" fork. For now it's a 24" but want to see the fork in the headtube with stem and handlebars inserted in the steerer, and the rear wheel built and into the dropouts first. That way I can have a better idea on how mush the geometry will be altered in either case.

[Ali C]

Definitely an internal headset (push in cups). I can see how the angled shape might be confusing but integrated headsets are fairly rare in trials and this is an old frame brought out before integrated was as common in the MTB world.

[Mark W]

10 hours ago, thousandwords said:

Will not order front wheel stuff for now as I need to decide whether I want to put a 20" or a 24" wheel in that 24" fork. For now it's a 24" but want to see the fork in the headtube with stem and handlebars inserted in the steerer, and the rear wheel built and into the dropouts first. That way I can have a better idea on how mush the geometry will be altered in either case.

The geo will be altered a lot, even just from the 24" fork. Most 20" trials forks tend to be about 360-370mm axle to crown, whereas 24" forks are going to be about 40mm longer than that. With a 20" front wheel at least you've limited the geometry change, but with a 24" you're obviously adding a fairly considerable amount more to that too (about 50mm or so). 

With a 24" front wheel, that's going to make that head angle really slack so it'll be worse on the front wheel, and the extra weight and size up front is going to make it harder work on the rear wheel. It's also going to make the reach of the bike much shorter, so it'll most likely feel even more cramped than 20" bikes typically do.

There are only really marginal benefits to a mullet setup on an MTB, and the benefits you have there don't really cross over onto a trials bike. Technically your T-Pro is already mullet anyway as you have a 19" rear wheel on it compared to the 20" front, but that's to allow the use of the much bigger rear tyre so it works out as effectively being 20" front and rear anyway (which is why Maxxis confusingly label their Creepy Crawler rear tyre as a 20x2.50", even though it won't fit 20" rims).

I rode a couple of those T-Pro frames and enjoyed them - the geo was fairly neutral and it felt quite comfortable to ride. I typically used a 180mm stem with some low-ish rise bars, but the 150mm should still be good with the amount of rise you've got on those bars.

A random one, but you may find that to make the frame last longer you'll be better off using just the bashring, rather than using the bashplate. That style of bashplate puts a lot of force into the middle of the downtube where the forward bash mount is, and it's not uncommon to see 20" frames crack and snap at that point. You don't have that issue with a bashring, as well as having some additional benefits like saving a significant chunk of weight and gaining more ground clearance.

[thousandwords]

Mark- point taken on the bash plate- thanks!

Yeah I figured geometry will be pretty altered but haven't considered all the finer points you listed, particularly the way it will alter the reach.

After reading your post though I started giving a 20" front wheel way more weight than before. Will probably still be last decision to be made in the build, and if I go with a 24" it might be just out of curiosity, as swapping front wheel to a 20" is just a matter of seconds, all I need is build both a 20" and a 24".

 

[thousandwords]

DAY 6

 

Primer came- frame fully painted.

Does not look anywhere near professionally painted but it was my first time painting a frame (first time painting any metal implement really) and the scope of the endeavor was multifaceted.

One, wanted to personalize the bike-check.

Two, wanted to learn how to paint a frame. Partly checked- the most important thing I learned is that I need how to learn to have patience until things dry fully. I was impatient at times- clear coat over paint too soon, peel masking tape too soon, etc and it shows. 

Three, needed to test the three metallic paints I used (copper, brass, bronze). Check, but with surprising results. I expected to like the copper the most, I don't. But the bronze really grew on me. Unfortunately it got the least use on the frame.

I have a Campagnolo Athema groupset I pulled from my road bike (replaced with Record) and I bought a steel road frame to build using that groupset. I will need to paint the frame, and I was thinking of using a combination of the same colors as in the Onza. Seeing the results, I will have to reconsider the whole paint scheme.

[thousandwords]

Ordered a bunch of stuff from Tarty.

Besides the rim, hub, spokes and sprocket already mentioned: chain (3/32), grips, rim tape, inner tubes, 19" tire (Maxxis Creepy Crawler), brake lever, aftermarket Hs33 pads (at Tarty's recommendation -Coustellier 8mm- as they mentioned over the phone that for only 6 pounds they can grind the rim for me but stock Magura pads are not a good idea with that).

Once all this stuff comes and it's on, provided the headset won't give me much grief, the only thing needed for the bike to be complete is a front wheel.

 

[thousandwords]

DAY 7

 

Ritchey headset came today, I already had the headset press out in waiting.

Once I checked a few cup dimensions by digital caliper, it went right in.

My worries were unfounded, both cups sit flush.

But there is a reason for it, and I had an inkling it might fit based on drawings found on Ritchey website- the entire height of the cups is 10 mm, out of which about 2 mm is the lip (sitting outside the head tube), and the beveled part (the one in contact with the head tube chamfer) is another 2-3 mm, so the straight part had to be less then 6 mm.

The head set is built around retainer/cages bearing, not the cartridge bearings that a majority of headsets I know of use. The retainer bearings are very slim, almost half the height of a cartridge bearing, hence allowing for a slim cup as well. It is the only ZS44/28.6|ZS44/30 headset Ritchey makes anyways so it was an easy choice.

 

I would be happy with a retainer bearing headset, except I have never used one before, so not sure how it will weather. One of the reasons I installed it as such is precisely to find that out. If the bearings do not last, it is easy to take cups out and install a different headset altogether.

And if I do not like the way it feels while turning the handlebars (gritty, etc), what I will probably do is take the upper cup out and install a cartridge upper headset like the FSA Orbit Z, as the head tube is deep enough on top to allow for a regular cartridge bearing cup.

For now it stays in as it is for testing. Fork has to be coming any day now so the initial testing (without a front wheel) should be happening soon.

 

 

[Mark W]

I remember from back in the day that we recommended open bearing headsets for those specific frames for that reason

Open bearing headsets still work fine. As long as you make sure you use plenty of grease when you install it you shouldn't have any problems realistically, and it shouldn't feel any different to a sealed headset in use.

[thousandwords]

Had an extremely busy week at work and in general so fell behind on the write-up, time to catch up.

 

Day 8

 

Had to travel for work Monday and Tuesday, and as Murphy's law has it, the shipment from Tarty got to my house on Monday and sat in the rain for 2 days in front of the door...

However, Tuesday evening when I got home, I was really excited to open it up! Rear wheel stuff (rim- preground by Tarty- tahnk you!, tire, spokes, hub, tube), grips, rim brake pads, rear brake lever, chain.

Got right into building the rear wheel and soon enough it was on the frame, pads went in replacing the stick Magura ones, brake lever and grips went onto the handlebars.