thousandwords

Happy to hear bottom cup not sitting flush is not that much of an issue! It would still be nice to find a cup that fits, but won't be worried any longer if I don't find that. I lucked out on the BB thread issue- ISIS BB already in (cranks, bash ring and freewheel as well) and went in smoothly first try! Just got an update saying that fork just cleared customs, headset is on the way too, so soon the headset press will come out of the tool box! Fingers crossed cups will fit in nicely.

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".

Thanks for all the info! Just bought the Ritchie on the link provided by ben_travis (thank you for the suggestion!). I still have lingering questions regarding fit, although you guys convinced me 100% it's a internal/semi-integrated design, mostly related to the height of the cup flange that goes into the headtube (just making sure it's not too tall, contacting the chamfered portion of the headtube before cup goes all the way in. Before ordering a particular headset measured the straight part of the headtube- about 9mm top, 6.5 mm bottom (the only difference between top and bottom, otherwise identical) and looked at a few different internal headsets. I even called Cane Creek, one of the manufacturers that have an ZS44/28.6/ZS44/30 (which is really the type of internal headset that would fit this headtube) and they confirmed my worries lol. The straight flange of their cups measure about 8.5 mm top and bottom, so the bottom one would be too tall for the Onza headset. I also sent an email to Onza (while not making frames any longer, they are still in tire business) in hope they have an archive with specs for the frame. But the Ritchie is a great start because it is inexpensive, so if bottom cup does not fit, it won't be such a loss. Besides, the top cup (inf act the whole top assembly, bearing, etc) will fit so I can use that. And even a non fitting bottom cup will give me a baseline for what a correctly fitting cup should measure.

Aener- thank you so much! Great points, and needless to say, once the HS33 calipers were in, the extra clearance was welcome, as you pointed out. Will stick with the 128 mm!

Hi all, Back with another question ha ha, this time about headsets. I just cannot figure out what headset is needed for this headtube. Internal diameter almost 44 mm. But milled at 45 degrees as for an integrated headset, with no internal cups necessary. Here are 2 pictures, apologies for the upside down caliper reading. Thank you in advance!

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.

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.

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.

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.

BB and cranks came today (man Tarty ships fast!) so I had my answer. Between the width of the crank head (where it interfaces with the isis splines) and the flare of the crank arms, there is an enormous amount of offset, so the crankarms clear the chain stays be a good 3 cm or so. In other words I could have gotten a much narrower BB, even an 108 and still clear the chainstays by a good margin. Will probably other another BB because now I worry about chain line lol, the freewheel is so much out with an 128 that the rear hub sprocket will be very far off medially.

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.

Thank you. I haven't decided yet on specific crank (Probably the trailtech sport lite splined) but I noticed that most if not all available cranks have an offset of 33-34 mm so so fitting purposes brand won;t make mush difference anyways (I just like the Trailtech because it comes with freewheel and bashplate preinstalled, plus Ali said in one of his bild vids that trailtech make some of the better freewheels and cranks if I remember correctly) I will bite the bullet and buy an 128 mm BB and hope Q factor is wide enough to clear chainstays. BBs aren't super expensive (at least not the Comas that is the only available 128 splined BB on Tarty) so if I have to start digging for a wider BB later I won't cry too much lol.

Has anybody ever ran into clearance issues (with chain stay) with an 128mm spindle bottom bracket and had to go wider? That's what I would like to order for a new build and I am a little anxious it might not clear. I have a spare 131 mm splined spindle and if I lay that thing across the stays it's tight...they apparently designed that particular frame for a massive tire clearance, although I do not know the exact numbers. Thanks.

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

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

DAY 2 Frame painting time

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.

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.

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

That's it for day 1. Maybe not much, but I'm happy.

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.

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.

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.

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!

La Bourde- your post really nailed why I wanted to get into trials. As I mentioned earlier, I have quite a few bikes. Every time I built a new bike, I built it in hope that it will make me ride longer and maybe more often (I do ride often though, I just feel that I could do better). I started with road, but at some point I found it a little boring. So built a triathlon bike, a single speed, a full suspension mountain (the one in the pics), a hard tail, etc etc just to diversify and add some variety and spice to the act or riding. However, I have moments when I feel something is missing. Granted, one type of riding and bike I have not added to the riding "portfolio" is downhill, as the idea scared me to death without even trying. (Will go on a short tangent here. That might be just about to change. Last Sunday I went with a group of friends for some zip lining. Boring as hell, but the course is abutting a ski resort, Berkshire East, that in summer functions as downhill park, We went to the resort restaurant for a bite, which gave me an opportunity to look into the park. They have one green trail, and they offer lessons for beginners. Once I got home I watched youtube vids of people going through it (it's called Sugar Line if anybody is curious); I could do that with my present skill. If I keep going and allow myself a leisurely pace of progression, I think I would tremendously enjoy it, even though I might never try the black/diamond runs. Enough about this though, it;s beyond the scope of this discussion). I've been thinking of it lately and I think I figured out why. It's utterly predictable and repetitive, even the mountain biking I do (granted it is the least so of all the types of riding I do). I am scientist. My brain craves constant, renewed challenge. Otherwise it gets bored to tears. And it occurred to me that trials riding offers that. Just nailed a skill or trick? There's a brand new one that you could start working on right away. So once this frame happened to fall on my lap so to speak, I got really excited about it and, like you said started working on basic skills on my hard tail. Yesterday I spent a few hours trying to really figure out the track stand. Never felt like giving up although it was a few hours of miserable failure (towards the end I started seeing actual progress, albeit timid). In fact I loved the struggle. Oddly, it reminded me of being young in school and trying to tackle harder math problems. And for the same reason I got a little excited about the downhill thing last weekend, although the difference is I have to drive 1.5 hours for that downhill park, but I live 5 minutes away from a state forest where I can practice skills all day long. So if I understand you correctly, as long as you are willing to trudge through disappointment (I am), it matters less what bike you have. If that is the case, and if a 26" will only bring marginal advantages, I can stick with the Onza then. And will say it again, this feedback is very appreciated!