First MTB tandem bu...
 

[Closed] First MTB tandem build complete. And tested!

Posts: 569
Free Member
Topic starter
 

Evenin' all,

I almost finished this two weeks ago but then had to make three attempts to get the correct Shimano Thru-Axle (not the SM-AX56, not the MT-500, the SM-AX58-just right!). I had a previous thread (link) for advice, so many thanks again to all on there. This is supposed to be for me and Mrs Gaidong to get out on the local trails but, as you see with the stoker saddle, slammed my 10 year old son can also get one (cue upset 8 year old daughter). I've gone cheapo but solido for the core: EXS alu frame for €380, bike-components.de special Fox 34s in 140mm pedelec, self-built Ryde Andra 40 rims on Shimano 36 spoke hubs (Zee rear, XT front) shod in Schwalbe NNs, XT/SLX transmission plus a spattering of of Easton Haven here, bit of Raceface Turbine/Chester there. Total build cost? Dunno and don't wanna know. First ride in the woods after the storms, gritty and grinny. Pretty happy with my front derailleur set up as it's supposed to be a top pull and I just bodged a Sideswing and ran the brake and two derailleur cables together on the NDS. Oh yes, Zee brakes on 203 mm rotors.

Off you go then, lay into the few pixels of lawn and hedge you can see - precisely zero sh1ts will be given :D.

err, it's the MTB tandem


 
Posted : 13/06/2018 5:27 pm
Posts: 44664
Full Member
 

That looks mighty fine.  I'd want much higher bars with a captains seat that high but other opinions are available.  I also much prefer SPds to minimise pedal / shin interface issues but it looks like a very capable machine.  Enjoy


 
Posted : 13/06/2018 5:31 pm
Posts: 3903
Full Member
 

That's impressive - the bike, not the lawn or hedge...

Seriously that's great work.

How many rings on the rear chainset?

I take it the front mech only moves one of the chains?


 
Posted : 13/06/2018 5:32 pm
Posts: 569
Free Member
Topic starter
 

Thanks TJ. I'm usually in SPDs but the missus and son are just starting out so I'm trying to minimise the fear points. The important issues are covered though; she likes red and I like green...

I know the saddle looks daft but all my bikes look like that and I've only got really sore shoulders to suggest it might not be ideal 😀


 
Posted : 13/06/2018 5:33 pm
Posts: 569
Free Member
Topic starter
 

Hi Dirk,

The FD was a bit of a shot in the dark. I'm running 24/36 steel chainrings (will swap to a 38T when I can find a 'middle' one. The FD is a M7000 jobby, so 2/3 speed, with a M8000 2/3 speed shifter. Honestly I just whacked it on, set the stops, and it worked straight off!

Cheers,

Gaidong


 
Posted : 13/06/2018 5:36 pm
 Bez
Posts: 7438
Full Member
 

Tidy. Get a normal seatpost as well, then you can get your daughter on there (my son rides ours with a rigid post, he's not quite big enough yet for the suspension post my wife has).

And one of these 🙂 parp


 
Posted : 13/06/2018 5:38 pm
Posts: 44664
Full Member
 

Is the timing chain one tooth out?  Its best IMO with the pedals in complete sync so when you stand up both sets are level - sometimes its not possible tho to get it perfect.

Remember - rule number one of captaining a tandem - make sure the stoker enjoys the ride!


 
Posted : 13/06/2018 5:39 pm
Posts: 569
Free Member
Topic starter
 

No, if I rotate one of the cranks a single link it looks even further out. Not sure why it's like that to be honest but I set it so I would hit the power (ahem) first to hopefully avoid the chain coming off.

Son stoker was happy. I mean, I scared him a bit but what's the point in being a dad with a 10 year old if you can't push his limits a bit.

I think I've got a spare 31.6mm seat post but really, I don't think I want my daughter on there just yet. She's such a dreamer she'd probably forget to hold the handlebars or something.


 
Posted : 13/06/2018 6:02 pm
Posts: 13554
Free Member
 

That looks great. Hope it brings you and your family many years of fun on the trails


 
Posted : 13/06/2018 6:19 pm
Posts: 11604
Free Member
 

For maximum points, swap one pedal and one grip front to back for the 'odd socks' look. That would be cool 🙂


 
Posted : 13/06/2018 6:20 pm
 Bez
Posts: 7438
Full Member
 

Surely you want the red ones on the port side and green on starboard? 😉


 
Posted : 13/06/2018 6:27 pm
Posts: 45988
Free Member
 

Now that looks like a right giggle...


 
Posted : 13/06/2018 6:47 pm
Posts: 569
Free Member
Topic starter
 

TJ, you were right. It was one link out. Just didn't look right when I didn't have the EBB tightened. All is well in the world.

Spooky, I am not a buyer of odd sockdom but Bez's port v starboard idea could be a winner. I'll have to do cut 'n shuts on the handlebars too!

Funkmaster, thanks for the wishes, my fingers are certainly crossed.

Riding it to work tomorrow morning, alone. It will be fun going through the security checkpoint and not smirking in front of the machine-gun toting guards.


 
Posted : 13/06/2018 8:02 pm
Posts: 6416
Full Member
 

Looks great, still waiting to get out on our recently converted from touring to MTB Dawes Discovery but Mrs DB has been ill 🙁

@Bez - ha ha looks like we're not the only one to have a hooter on the back - we also have a voice activated brake operated by the stoker too


 
Posted : 13/06/2018 8:56 pm
 Bez
Posts: 7438
Full Member
 

Bez’s port v starboard idea could be a winner

Let me know when you get to the point where you find out why it really couldn't 🙂


 
Posted : 13/06/2018 9:10 pm
Posts: 2033
 

Nice work! Glad TJ pointed out the timing chain one-tooth-out error. Apart from that, it looks great.

Is that a Thudbuster? I've recently moved the rear saddle on my Thudbuster forward as stokers were complaining about the ride being too recumbent, but they're great things.


 
Posted : 13/06/2018 11:17 pm
Posts: 569
Free Member
Topic starter
 

Aye, 'tis a Thudbuster LT.

Rode to work today with Mrs Gaidong today (dropped her at the gate and then she ran home). First issue, she is a grinder (of sorts :D) and me a spinner - a cadence compromise looks mutually dissatisfactory at present. She liked it though, despite her worries of me guffing in her face all the way (got my son a beaut yesterday). Had a few turns around the base with work colleagues and rode home alone offroad in the mud. All good.


 
Posted : 14/06/2018 5:28 pm
Posts: 44664
Full Member
 

We had to do the cadence compromise as well - you do get used to it.


 
Posted : 14/06/2018 5:32 pm
Posts: 648
Free Member
 

<div class="bbp-reply-author">
<div class="bbp-author-role">
<div class="">Subscriber</div>
</div>
</div>
<div class="bbp-reply-content">

Bez’s port v starboard idea could be a winner

Let me know when you get to the point where you find out why it really couldn’t

just take bodies of the front right axle and back left axle and swap

</div>


 
Posted : 14/06/2018 5:34 pm
 Bez
Posts: 7438
Full Member
 

Most pedal bodies are side-specific too, though.


 
Posted : 14/06/2018 5:39 pm
Posts: 648
Free Member
 

It’s worth a try though if only for a photo.


 
Posted : 14/06/2018 5:43 pm
 Bez
Posts: 7438
Full Member
 

Photoshop's quicker 🙂


 
Posted : 14/06/2018 5:47 pm
Posts: 12265
Full Member
 

First issue, she is a grinder (of sorts :D) and me a spinner – a cadence compromise looks mutually dissatisfactory at present.

Just put a smaller chainring on the front!!

(yes, I do know it's a stupid idea, but so was the port/starboard pedals)


 
Posted : 14/06/2018 8:04 pm
Posts: 17319
Full Member
 

Very nice. Timing chain alignment is a whole can of worms. Captain leading by two links is common, as is stoker leading. As per TJ, I'd have some taller/wider riser bars, you are the one balancing that tandem, and it's a bigger workout than a single bike. Practice standing up together, on road tandems it's normal for the stoker to stand up to adjust position and relive the pressure. They get beaten up a lot more, so nice to see a thudbuster. Call "up" and "bump". Often. Or you'll be looking for a new stoker!

It's not widely advertised, but the stoker gets a much better time. And is always right.

The rule of tandems:

"Wherever your relationship is going, you'll get there faster on a tandem"

tandem@hobbes is a bit quiet these days of social media, but I've been on there for years.


 
Posted : 14/06/2018 9:14 pm
Posts: 4954
Free Member
 

Will we be seeing you compete at the Roc race this year?


 
Posted : 14/06/2018 9:23 pm
Posts: 569
Free Member
Topic starter
 

No Roc for me this year. I like the landscape but I can’t stand the traffic jams on the trails. A lady team from my club did very well on the Roc tandem last couple of years, first in class or something. I built one after ogling theirs (tandem).

I’ve been calling out the bigger bumps so far but certainly am not communicating gear shifts enough. Got a 750 mm bar for me and started cutting down the stoker’s bar yesterday (725 to 700) as they have enough leverage to spin my seat post however much I tighten it!


 
Posted : 15/06/2018 6:39 am
 nbt
Posts: 12469
Full Member
 

Looks great though like TJ I'd want pilot handlebars a little higher - arse high nose low might be great for racing but not sure I'd want it on my tandem!

Mrs NBT can't use SPDs anymore, so we have flat pedals with a toe cage for her on the back (I use SPDs on the front). When we first tried off-road tandeming I had JUST converted Mrs NBT to flat pedals so that's what she used - first serious downhill she got a faceful of my back as she was jolted forwards out of the saddle when we went over a bump. We used SPDs for a while but as above have now gone back to flats with a cage, would recommend you consider that for the sake of keeping the stoker in place


 
Posted : 15/06/2018 9:28 am
Posts: 569
Free Member
Topic starter
 

But but but I’m not arse up head down. This was the largest size tandem EXS (cheap) do and it’s too small for me is all. I’ve got girt long arms! Zoom in and you’ll see the bar is a 20 or 30 mm rise on a Chester stem. It’s all pretty solid.


 
Posted : 15/06/2018 9:49 am
Posts: 0
Free Member
 

I would narrow the rear bars down even more as they are only somewhere for the stoker to rest their hands. If they are too wide then you will be forever catching them on trees and gate posts as the rear cuts in on the corners. like this.............. The fronts are 720mm, rears are 580mm. 700's will catch on everything especially on narrow single track.


 
Posted : 15/06/2018 7:14 pm