TanTan FM10 29/27.5+

[GuitsBoy]

Hi everybody, I am having a question here regarding the fork length. I didn't see TanTan indicating the correct theoretical fork length. At least I didn't find it. When they say that the frame travel is 150mm, I assume I can't use a fork with 160mm which has a bit a too long overall length? I guess it would destroy the geometrie and the way how it feels and how the bike behaves while ridding, isn't?
Maybe you guys who bought this frame already may help me? What is the fork length of the fork you chose? Do you think it would work with a fox 36 grip 2 29wheel 160mm Fork?
I would really like to buy this frame but I am a bit insecure with these figures, also with the shock length, after I read the previous posts... 

Thank you very much!

I just took a guesstimate that a common fork would be the Fox 34 29er 150mm travel.  That fork has an axle-to-crown measurement of 557.  I stretched my 27.5+ Manitou Mattoc out to 150mm travel which gave me 559mm axle-to-crown which is pretty close to the fox.    Your Fox 36 has the same axle to crown as the similarly sized F34, so at 160mm travel you have 567mm axle to crown.  IMO thats not too bad, and within reasonable proximity to  the intended fork size.  Between the two, I'd always rather go slightly overforked than under forked.  Certainly the 160 shouldn't slacken out the head tube angle to the point of it being dangerous.  If it were me, I'd run that fork without hesitation.

[GuitsBoy]

Received another message from Tan Tan.  The parts have been designed and are in production, heading to paint shortly, then shipped as soon as possible.    They confirmed the new parts have been redesigned for proper clearances.  Old parts can be discarded.

[MX72]

I also got a similar response.  The rep said they did make updates to the design and the issue is fixed.  So I am moving forward with the order.  It will probably be at least a month before it arrives but I will update when I receive it.  I'm excited to get this thing built!

[arrkaye]

That's great news. Mine is yet to ship so I'm just waiting for confirmation they will include the updated pieces on mine.

[chinerrider]

Hi everybody, I am having a question here regarding the fork length. I didn't see TanTan indicating the correct theoretical fork length. At least I didn't find it. When they say that the frame travel is 150mm, I assume I can't use a fork with 160mm which has a bit a too long overall length? I guess it would destroy the geometrie and the way how it feels and how the bike behaves while ridding, isn't?
Maybe you guys who bought this frame already may help me? What is the fork length of the fork you chose? Do you think it would work with a fox 36 grip 2 29wheel 160mm Fork?
I would really like to buy this frame but I am a bit insecure with these figures, also with the shock length, after I read the previous posts... 

Thank you very much!

I just took a guesstimate that a common fork would be the Fox 34 29er 150mm travel.  That fork has an axle-to-crown measurement of 557.  I stretched my 27.5+ Manitou Mattoc out to 150mm travel which gave me 559mm axle-to-crown which is pretty close to the fox.    Your Fox 36 has the same axle to crown as the similarly sized F34, so at 160mm travel you have 567mm axle to crown.  IMO thats not too bad, and within reasonable proximity to  the intended fork size.  Between the two, I'd always rather go slightly overforked than under forked.  Certainly the 160 shouldn't slacken out the head tube angle to the point of it being dangerous.  If it were me, I'd run that fork without hesitation.

Thanks for the response. I am most probably going for this idea!

[northup]

I heard back from Lisa at Tan Tan via Alibaba messaging. I pointed her to this thread and asked if she'd seen this issue. Her response was:

yes . I have check . We have changed the mold of the connecting rod . now frame have not this problem . don't worry .

I'm going to continue with my order and see if anything is actually different.

[GuitsBoy]

By the way guys, the Flip Chip offset is actually 13mm.  Not 10.  Not 15.  Its 13.   Not sure the reasoning, but its close to a half inch.  Rear travel is not impeded by anything other than the tire hitting the seat tube.   IMO a 185 shock should fit just fine, and you probably wont hit the tire to the seat tube at full compression.  A 195 should would probably also work in the 200 position, as long as the tire clears the seat tube, it will just sit a little lower.   More questionable is the 185 size.  With the 13mm offset, the 185 shock is actually going to put the seat stay arch 2mm closer to the seat tube than my 200mm shock, and clearance was already tight.

But all this goes away since nobody knows what the new casting for the rocker piece looks like.  It might have more clearance all the way around.

[emu26]

Possibly because the two holes, when located in their required position, don't sit in a straight line with each other relative to the line of shock travel so the straight line dimension is actually to two different points on an arc, not two different point along the same line. See on the geo diagram that has both dimensions on it, the line showing what is being measured aren't parallel to each other.  I don't know if that is enough to make up for the 2mm but it will take some of it.

If you have your shock out then you could lay your bike on it's side and measure the 185 from eye to eye and see what happens.

Either way, good to hear they have got a resolution. Hopefully you weren't the one that brought this to their attention otherwise they have done the rework very, very quickly and I wonder if they actually did the required testing on the altered parts.

[GuitsBoy]

I have a temporary fix for my clearance issues while I wait for the new parts to arrive, though I'm not going to publicly post what it is.  But anyway, I got another ride in on the new frame last night.  This was a 13 mile ride, the first half is just grueling relentless climbs, and the second half is fast, weaving trees, and some tech.  the climbs were a bit challenging, and as the miles went on, I developed some ghost shifting.  Towards the end of the first half's climbs, I noticed some tire rub and finally stopped to check things out.  The pivot at the rear axle drive side had completely come loose.  The bolts were just floating, completely disconnected.  The seat stay and chain stay were completely separated.  I cant believe I didnt lose the bolt.  Anyway, go over and loctite all your pivot bolts.  Its not enough just to snug them up.  Put fresh loctite in there just to be sure.

After fixing the pivot issue, the bike was climbing and shifting much much better, and still felt supple on the downhills.  Ripping through the trees really felt amazing.  It felt like I had a TON more traction than my previous FS27 frame.  Really leaning the bike over and pushing into turns the bike didn't ever feel like it wanted to break loose.  Pedaling on flat and mild uphills I didnt notice any appreciable bob with the shock set to pedal platform level #2 of 4.  I was very happy with how it handles fast moving singletrack.  Uphills were a bit tougher, but I really need to go back and revisit those climbs now that the pivot and shifting are fixed.  I also have a few more pedal strikes compared  to my last frame, but always on compression events.  I may need a touch more air in the chamber to ride a little higher.  My sag was closer to 35% which is a bit much for me, though It felt great on the downhills.

All in all, it was a good ride, and I finally felt quite happy with the frame.

[chinerrider]

I have a temporary fix for my clearance issues while I wait for the new parts to arrive, though I'm not going to publicly post what it is.  But anyway, I got another ride in on the new frame last night.  This was a 13 mile ride, the first half is just grueling relentless climbs, and the second half is fast, weaving trees, and some tech.  the climbs were a bit challenging, and as the miles went on, I developed some ghost shifting.  Towards the end of the first half's climbs, I noticed some tire rub and finally stopped to check things out.  The pivot at the rear axle drive side had completely come loose.  The bolts were just floating, completely disconnected.  The seat stay and chain stay were completely separated.  I cant believe I didnt lose the bolt.  Anyway, go over and loctite all your pivot bolts.  Its not enough just to snug them up.  Put fresh loctite in there just to be sure.

After fixing the pivot issue, the bike was climbing and shifting much much better, and still felt supple on the downhills.  Ripping through the trees really felt amazing.  It felt like I had a TON more traction than my previous FS27 frame.  Really leaning the bike over and pushing into turns the bike didn't ever feel like it wanted to break loose.  Pedaling on flat and mild uphills I didnt notice any appreciable bob with the shock set to pedal platform level #2 of 4.  I was very happy with how it handles fast moving singletrack.  Uphills were a bit tougher, but I really need to go back and revisit those climbs now that the pivot and shifting are fixed.  I also have a few more pedal strikes compared  to my last frame, but always on compression events.  I may need a touch more air in the chamber to ride a little higher.  My sag was closer to 35% which is a bit much for me, though It felt great on the downhills.

All in all, it was a good ride, and I finally felt quite happy with the frame.

Thanks for sharing your experience.

I actually ordered the frame, but they canceled my order right away, as I chose online bank transfer as payment method. But unfortunately I figured this out after the amount was already discount from my bank account only..... The money came back automatically though. But I lost more than a week, so I have to place the order again....and then choose another payment option. They also didn't mention that they can't ship to my country, so I have to pay an extra fee to ship with DHL to Switzerland...
So, all a bit weird.

I was thinking to replace all the pivot bearings right away, then as you suggest, loctite the screws (red or blue loctite? Blue should be strong enough?). I don't believe they use proper bearings, and good quality bearings used in the machining industry are not so expensive, so I think it's worth to do it right away when assembling the bike.

Would you mind sharing the bearing sizes? I hope these are some standard bearings? I would like to order them in the meantime, so that I got then already when the frame finally arrives here...

Thank you very much!

[GuitsBoy]

The rear pivots are 698RS bearings.  Those are the only ones I know of since Ive already been in there.  I did manage to lose a spacer between the chainstay and seatstay, so I had to rig something up with washers I had on hand.  Also, I should note that these bearings are epixied in, or otherwise using some bearing retaining compound.  Mine did come loose on both sides, so I pressed it back in using loctite 609 (bearing retaining compound).  Ive only had a couple short rides, but so far its holding.  A couple quirks, but no big deal.   Anyway, Ill try to get the rest of the bearing numbers for you next time I'm in there.  But I would think those rear pivot bearings take the biggest beating, so start there.

[emu26]

Am very tempted with this. Just found an AlieExpress seller that has it under $1k Aus with free delivery.  I have an old RP23 that will fit and possibly a Monarch RCT3+ Debonair depending on what happens with a frame warranty claim.

Hey Guitsboy, I just realised you're on MTBR and posted some cracking shots in the star gazers club thread.

[GuitsBoy]

Thanks Emu.  That reminds me, I gotta update that thread, I have quite a few more shots to post from the last few months.

[emu26]

Still waiting for those stella pics. 

Amended frame part

[GuitsBoy]

Nice, did the seller provide that image?  You dont have the part in hand, do you?  Either way looks good.  I havent been riding much, but when I do, I'm still riding the frame now that its developed some clearance.  I also swapped out the 40mm shock hardware with an enduro roller bearing setup.  The 54mm side already has bearings.


And I updated the sky watchers thread on mtbr for ya...