# Surly Big Fat Dummy + child seat SUCCESS (with pictures, Yepp Maxi Nexxt)



## high_desert_mud (Jul 22, 2017)

Just finished making and adapter and mounting the Yepp Maxi Nexxt (2017) child seat on my BFD!

The kid loves it!!!

If you are reading this thread, you know the problem. The deck is too wide to fit any of the stock ways any brand of seat mounts, and that width also creates problems for the legs / foot-rests / lawyer guards.

we looked at just about every brand we could find. 

Hamax Caress - looks like a great seat, and i liked the spring and recline feature. However I emailed the mfg who sent pics, and the center 'tunnel' of that seat is a pretty firm 6 inches. It was the most restricted of any I looked at.
Bobike Exclusive Tour - loved the side head rests. We were initially concerned this would block the kid's view; but now that I have him on the bike, (and he has fallen asleep of course) I am re-considering. It looks to me like it would mount identically
I saw one user who successfully got a Yepp Maxi (non-next) mounted on the dec, but it took hacking corners off the deck a slightly modified easy-fit adapter. I didn't want to destroy my perfectly good deck 
The Yepp Maxi (non-Nexxt) would probably work just fine on my adapter; but I thought the way the plastic worked on the 'separate' bottom section of the Nexxt would make for a cleaner look if i needed to 'splay' the legs out significantly.


In the end, besides getting great pictures of how the Hamax was waaay to narrow, we just couldn't get precise enough measurements from anyone to know for sure ... so sprung for the Nexxt.

Test-fitting, i found that if mounted ~3 inches up from the deck, the legs were just barely pressed on the deck, and it fit/removed without difficulty.

So a trip to the local metal house, and some time with a welder, and boom !  I'll add dimensions below; this doesn't take much skill with steel, and any professional could whip this up from aluminum in a couple hours shop time. I do not have a tubing notcher, and I haven't welded in a few years (or ever professionally), which makes my welds "not pretty" ... but in steel of the thickness i chose i'm confident its much stronger than the 1/8" Aluminum deck it is bolted too


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## high_desert_mud (Jul 22, 2017)

One great thing about using the existing grid on the deck is if there is a 2nd passenger, or i change my mind on placement, i can unscrew it and bolt it anywhere further aft. Or 50mm further fwd. The rails themselves are ~10 inches long, so the seat has some leaway there, too.


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## high_desert_mud (Jul 22, 2017)

the grid of existing holes I used are 

50mm fore/aft on center
90mm left/right on center
nice and oversized for the M5 grade 8 bolts i used to screw from the bottom (I did not build any jigs for this, just tacked it together freehand before welding; so my angles are not perfect)

The rack itself:


is made from 065 wall steel tube, 1/2" nominal.
a 1/2" long steel plug is welded in the bottom of the verticals, then drilled/tapped M5
around 6 inches wide
10 inches long
When the seat is removed, it fits a 6-pack perfectly (I widened and lengthened it a bit to make sure this happened 
















I used a nylon washer to help the interface mate cleaner, and prevent any rubbing.


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## high_desert_mud (Jul 22, 2017)

If I come back to this project, i'll probably make a rack with a pivot and lock, to recline. I foresee the kid falling asleep a LOT on this  

The 5" tires are soooo much smoother than my friends Yuba. 

For good measure, i build a simple kickstand, too, which you can see in the top post. I didn't get time to finish my locking mechanism, so I have a quick strap i hold it up with for now.

I have to say, this is one, if not the, best bike i have owned. It handles remarkably well on trails for what it is, and there is some epic trailbuilding and family bikepacking I'm dying to get to. 

So far I have mainly just been commuting 10 miles each way on it. (not the BEST use for Minions, but yolo).


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## austinlw (Sep 11, 2013)

Very nice job on this one HDM.


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