quick question on adding rear rack mounts
 

I have a baby/toddler who likes to ride around with me.
Currently have a seat on a rear rack, all is well.

Except that I'm switching bikes, Diamondback Trace EXC
the new bike doesn't have any rear rack holes.

Considering a seat-post clamp with rack mounts (seems really easy, and I can get it today at a local store)
something like this http://bikeisland.com/cgi-bin/BKTK_S...ls&ProdID=1541

vs.
tubus stay mounting clamps (more involved, have to order online)

baby is 21lbs right now.
do you think it’s safe to go either way?
personally, I believe both options are good. but I don't have any experience with these.

I think that the brackets will be tighter with the tubus option - (b/c they'll be shorter)

thanks for your insight.

sincerely,
ryan

two options pictured for reference

http://bikeforums.net/attachment.php...hmentid=512117http://bikeforums.net/attachment.php...hmentid=512118

I wouldn't trust the seat post mount.

I don't think it's safe to go either way but no way in hell would I trust the seat post mount.

I wouldn't trust the seatpost mount.; it seems like it could rotate around the seatpost.

I've used the Tubus mounts, and they're very good.
I like the 2-bolt design; one bolt holds the clamp on the stay and the other bolt holds your rack mount.
They come in several sizes, so measure your seat stays and order the correct size.

To be clear, I'd trust the Tubus mounts for the upper mount, but not the lower mount. If your new bike doesn't have any eyelets down by the axle, then you should use a rack that connects to the axle.

Works fine, seat staz mounted. One click to remove,

https://www.bike24.com/1.php?content...ge=3;orderby=2

I wouldn't trust any temporary clip on mount with you baby.

the baby will probably outgrow the rack weight quicker than you want to stop hauling them around, have you considered a small trailer? you can get more than one hitch for each bike and then it's a matter of a single pin and you can use any bike you want. also trailers are good past 50 lbs, sometimes much more, and can be used for other things.

I would trust either arrangement. Don't like seat-post mounted racks, but in this case the seat-post clamp is only providing the top attachment and the weight of the child and seat is being supported by the lower support at the rear dropouts of the bike. I used a child seat with the top support attached to clips around the seat stays and generally preferred it to using a trailer due to the closer interaction with my daughter. When she outgrew the seat she became the stoker on the back on our tandem.

I'm assuming here that you're talking about a rack with legs, and that the frame has fender eyes. If hat's not the case, stop reading this.

The carrier's legs are what carries the load, and the forward mount, whether st the post or stays, only provides stability. Mostly it's of the fore/aft type (try mounting a rack without attaching the front), but there's also an element of anti-sway. The anti-sway feature's importance depends on the rack, with some getting good rigidity from the legs alone, and others not so much. But keep in mind that most of the better racks also allow a single strap to the brake bolt, which provides no anti-sway benefit at all.

So, IMO, either mount will serve, except that on a taller frame, the clamp may be high compared to the rack deck, calling for a longer strap, and reducing rigidity. One minor benefit of using 2 seat stay clamps vs. the single post clamp is redundancy. If either clamp bolt loosens and falls out, the other will keep the rack attached and keep it from flipping backward. How much that matters depends on how you are about general maintenance, and in any case a safety strap could be improvised if you feel it's warranted.

many good replies, thank you

correct, the rack is supported by legs. the top brackets are to keep it in-line.
the geometry looks to work fine for either setup that I mentioned.

the seat post mount has a threaded hole on either side.
the two brackets for the rack would attach separately to the seat post mount
so there would be four mounting points for the rack, two legs, and two upper support arms.

Cheers and thank you all!

lots of folks pushing me to use a trailer. not just on this forum, but everywhere.
I understand the reasons how it could be safer. but I think there are pros and cons. I agree with you, closer is better, for me.
cheers

local shop has the seat post mount and it's only $12. I will use this initially. check it's rigidity and determine if it's safe.
if it's not looking good, I'll go with the tubus stay mounting clamps.

I just wanted a hear that someone else has used one of these mounts successfully for a rack with a child seat on it, which I did. So thank you all again.

Hell, if it breaks, I'll just make another one! :)

Of all the bicycle mounted systems, the one that has one part fixed to the seat post tube, and the seat attaching to that part is the one tested for biggest weight. About 25 kg. Also, steel rails that attach to the seat stay mount provide a bit of a spring dumping for big bumps. It has worked fine for my friends for years, I also decided to go for that one.

A friend who's been through all the stages: seat, trailer, kid on her own bike said that once the child is over 3 years old, it can go into trailer, but up to that time, it's better when it's closer - much less likely to feel uncomfortable, start crying etc. I took his advice.

Strength and rigidity is not the issue, fit is. Depending on the size of the bike, one of two options may fit better. For example, on a very small frame, the mounting hardware may not extend far enough for the seatpost mount to work. Conversely, on a big bike, you might not be able to get the rack level when attaching the mounting hardware to the seat stays. Sometimes too, trying to attach the rack to the seatstays interferes with the brake cable or caliper arms.

That seat post mount is going to be more sturdy (for stability, not for weight bearing) than those small clips. I have 2 different bikes with regular racks both mounted using a seat post mount just like that, and they are rock solid.

For weight bearing, the rack/seat needs to mount to actual rack eyelets or the actual wheel axle.

I suggest you start shopping for a child carrying bike trailer..

Unstated is the bottom dropout mount of the rear rack .. that is the weight support. what is it/they?


Topeak sells a rear rack child seat combination Topeak® Cycling Accessories ? Products - BabySeat? II & BabySeat? II Rack

you can probably buy a second of the same rear rack

awesome update.

I ordered the bike from REI.
$2800 bike
on clearance for $2100
plus I used a 20% off clearance coupon
$1680 total!

REI is great to deal with in the event of an issue with the bike.
plus they assembled the bike at no charge, the same day it arrived to the local store.

I must have gotten one of their last ones, no more showing in stock
https://www.rei.com/product/886432/d...-exc-bike-2015



I was looking for rear rack solution based on the review on this site:
https://electricbikereview.com/diamondback/trace-exc/
and especially the VIDEO (towards the bottom). nice lengthy review.
however, he shows a bike without the threaded upper holes for a rear rack. must have been a demo.
it did show the bottom holes.

you can't believe everything you see on the www.

b/c my bike came in yesterday, and it has the holes on it! they are rated for 50lbs.
all this stress over nothing.

thanks for all of the replies.
I hope the information will help the next soldier.

already have my rack installed, and all is well.

cheers

The reviews on that Diamonback e-bike don't inspire much confidence. One 1-star review, and even the 4-star review lists a bunch of issues.

I only saw two total reviews.
I believe they have updated a few things.
for the price, I'm extremely happy.