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Can anyone compare the OEM SBBN025 strap to Isofrane?

5K views 18 replies 12 participants last post by  Robotaz 
#1 · (Edited)
I'm not sure how many different rubber dive straps Seiko has used. I know that the rubber strap that came with my SBBN025 ('New Darth') is dramatically different than the stiffer strap that came with SKX watch. I've also read several people comment about how some Tuna straps are softer than older ones were etc, so that's the reason I specify this particular watch.

EDIT: It appears that my Seiko OEM strap is a B22.

I've never handled an Isofrane.

I like the appearance of the Isofrane in pictures better than this stock strap, but I find the stock strap very very comfortable. It's soft and has just the right about of stretch/give to get a really great fit with the hole spacing in any condition. I think the degree of stretch is just about perfect.

The thing that's not my favorite about the stock strap would be the the aesthetics of the wavy areas next to the watch, but I'm wondering if that area provides just the right amount of extra 'give' to more or less just be the perfect buffer for tension.

I don't care if the Isofrane is soft, I'm just curious about how much stretch or give it has. It looks like it has short hole spacing which I do like but if it is considerably stiffer than the OEM strap I may not spend the money for it.

I've noted numerous positive reviews for the Isofrane specifically on Tuna where people begin by describing the OEM strap as 'terrible' or 'not very good.' I wonder if they are discussing an older OEM strap of if those statements should warn me that I just may subjectively disagree with the reviewer.


So yeah the cliff's notes or 'too-long-didnt-read' is:
I really like the OEM strap fit and feel. I like pics of Isofrane better. I probably would not buy an Isofrane if it was considerably stiffer or had significantly less stretch. Can anyone help?

Thanks in advance.
-nolte
 
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#2 ·
Isofrane is significantly softer and more ply able without being a lint magnet. Best rubber strap on the market. Bonneto Cinturini sells a Seiko flat vent styled strap in almost identical rubber (BC 284 I think?) that is as good but easily a third of the price with an OEM look.
 
#4 · (Edited)
I'm in the minority, but I found the Iso's to be very uncomfortable to my wrist. Always pinched the sides of my wrist, when adjusted to not slide around.

Iso's are softer than previous gen Tuna straps, but nowhere (!) near the new gen compound. They don't have the "stretch", or pliability either.
 
#5 ·
I have an ISO, old Z22 (SKX stock rubber band) and the Z22 new Turtle rubber band.

Here are my observations:

SKX Z22 - Garbage - like wearing a shackle - do not use
ISO - PIA to get strap on wrist and adjust keepers. Once in place you don't notice it's there
Turtle Z22 - absolutely love this one - super pliable and comfy and easy to put on. I'm not using it in case I decide to flip the watch (don't ask me why cos I love my turtle too...)
 
#7 · (Edited)
I'm fairly sure both the old, and new gen SBBN straps are labeled B22, even though they are completely different materials.

Edit... They are the same part #, just checked my SBBN017, it's also B22.

 
#8 ·
I had the Isofrane and sold it because it was very uncomfortable. Thick and definitely not soft at all.
To be clear, a very good rubber and perfectly made, I'm sure it is a terrific tool for divers, but for desk divers like me it is simply not ok.

Inviato dal mio SM-N910F utilizzando Tapatalk
 
#10 ·
The strap that came on my SKX was like hard plastic, I took it off immediately and replaced it with a Bonetto Cinturini 284 and never looked back.

The Seiko silicone strap (marked B22) that came on my SBBN033 is lovely, extremely soft, supple and stretchy. It's squidgy silicone basically. When new, the coating on it gives it a slightly graphite grey colour, makes it very silky to touch and no lint sticks to it. I've owned the watch since late last August and with the exception of the last 2 weeks when I got a steel bracelet for it, I've worn it almost daily with the rubber strap on the wrist, and also over a wetsuit under water and swimming in the pool and this has worn away all the "non stick" coating. I get a tiny amount lint on the rubber now but still nothing at all like other silicone straps I've had in the past - the Seiko one gets my thumbs up on that front. Seiko have supposedly made a more tear resistant blend of silicone rubber for this strap but how accurate this is I've no way of telling. The stretch in the strap makes it comfortable with expanding hot wrists and the corrugated, wavey part gives a nice stretch to cinch down on a squashy wetsuit.

I also have a 22mm Isofrane strap. It's good quality, feels strong and tear resistant and gives the impression it'll last a very long time and is supple considering it's thickness - but ridiculously over priced if you ask me. I find the actual thickness of the strap a bit much for my skinny wrist, I have a lot of extra strap over-lap so a lot of double thickness rubber on the underside of the wrist. The vanilla smell is the same as BC straps, it also feels like the same rubber as a BC strap, just thicker as part of the Isofrane design - if someone told me they were made in the same factory I'd have no reason to doubt them. In the almost 4.5 months I've owned my Tuna I've never even attached the Isofrane to it - the original Seiko one is just highly comfortable and matches the watch design perfectly (IMHO of course). Ultimately the Seiko doesn't feel as strong in the hand as the Isofrane. My gut feeling on this says that if you got the two straps side by side, put a small nick in the edge of them both and then stretched them, the nick would develop into a cut that would spread across the strap at a lower level of force on the Seiko than on the Isofrane - that's probably the best way I can describe the mental image you get going by the "feel" of both rubbers in the hand.

Incidentally, the BC284 strap that's currently on my SKX looks all right on the Tuna too. It looks more old school though, would suit an earlier Tuna better. I prefer the Seiko strap that came with the SBBN033 over the BC one on that watch. Probably the most telling thing after all this is that fact that I've never even put the Isofrane on the Tuna, it's just sitting in a box with other straps.
 
#11 ·
To the OP - I mentioned somewhere else that I'd stick a pic up of the different buckle I put on the original Seiko rubber strap. This is it:

Buckle Fashion accessory Belt buckle Font Metal


Available here: (SEI-BU20-445P) 20mm Seiko Sport Type Polished Stainless Steel Watch Band Buckle 25 Jewles Rotomatic Watch, Automatic , Manual wind Vintage , slim quartz watch Tungchoy:

Of course there's nothing at all wrong with the original buckle, it's just a bit plain and looks like cost cutting a bit (at least the one on my SBBN033 is, maybe better Tuna's have better buckles, I don't know?)



The new one looks classier and befits the rest of the Tuna's quality. The original felt like pressed steel whereas this one feels like a much more substantial piece. It's also a compact size - I dislike huge buckles. I went for the polished version of the buckle over the brushed. The reasoning being: (a) The SBBN033 has a polished shroud, (b) there are polished, chamfered edges on the Tuna keeper that it would match and (c) I could always brush the finish afterwards if I didn't like the polished look.

Buckle Fashion accessory


If you look at the tang on the first pic I posted you'll notice that although nicely made, it's quite slim. I think it was originally intended for a leather strap and on the Tuna rubber it looked a little lost in the holes. I took a wider tang from another older buckle I had just lying about in the "watch crap" box, trimmed it to length to fit properly on the new Seiko buckle, then slightly widened the depression on the buckle that accepts the tang with a Dremel so it slotted in nicely.

Lastly and completely unnescessarily, I replaced the Seiko buckle spring bar with a Marathon one. I know there's nothing wrong with the original at all, my watch OCD mind just likes the fact that the end pieces on the Marathon bars stick out more and go completely through each side wall of the buckle. OTT yes but it just gives the impression of greater security

Audio equipment Office equipment Technology Electronic device Typewriter
Metal Rock


Side by side:

Fashion accessory Metal


Overall impressions on the wrist are that it makes the strap look much more expensive and a higher quality.
 
#12 ·
Yeah I do def agree that buckle looks quite a bit better than the one they put on there. Mine is all blacked out and I don't see a PVD one there but I will keep my eyes peeled for one. I like it.
Today mine's on a canvas strap but here is my rubber strap next to it.



Thanks for posting that. I agree changing the buckle improves it, and I don't think I would have thought to do that.
 
#13 ·
The strap on my brand new 025 is great, and I've got an ISO as well, but I'm in that minority that doesn't like them much either. I don't like dealing with the clasp, And it doesn't look great. The all black seiko buckle and retainer look perfect.
I do like that tuna on the canvas, might try that with one of mine.
 
#14 ·
To the OP: a bit late to this strap comparison party but if it helps, I will throw my 2 cents in. First and foremost, the Isofrane is an expensive strap; however, it is also a durable and probably bar-none one of the best rubber dive straps out there (if you can afford the Darth - $100 bucks for an Isofrane kind of sounds like a moot argument) - it is also one of the best looking aftermarket straps you can put on a Tuna - IMO. Second - Seiko has come a looooong way in the quality of their rubber straps on higher end models (like Tuna's :)). When I received my SBBN025, I immediately threw it on the wrist and thought 'wow, this strap is pretty awesome: supple, right amount of thickness, awesome blacked out keeper/buckle, 'fat' spring bars, and the 22mm metal sleeves inside the spring-bar openings in the strap so the spring-bars themselves do not contact the rubber (first Seiko I've ever owned that had those?). I compared the SBBN025 rubber to my SBBN017 and there is a difference in the quality and feel. While the SBBN017 was 'ok', I ultimately put it back in the box in favor of wearing it on the SBBN015 bracelet full-time (amazing bracelet/feel/look). Back to the Darth - I was hell-bent on throwing on an Isofrane because that was all I heard about and the pics online did give it justice; however, after mounting the Iso w/DLC RS buckle I immediately noticed the fit seemed 'off' compared to the OEM strap? Looks - amazing/Fit - not as good as OEM (for me). The best way I can describe the fit is the Iso makes the Darth feel a bit more elevated on the wrist as the strap cannot lay fully flat (180 degrees if sitting on a desk) as the 5.5mm thickness at the lugs seems to have minor interference (much more pronounced on Emperor Tunas). I'll still keep the Iso kit as a solid back up for when my OEM strap gives out, but for now I like the comfort/looks of the OEM, plus the security of the fat spring bars so I know nothing will get out of whack (btw - if you go Iso make sure you get some skinny/fat tip spring bars, I don't subscribe to the spit on the 'ole bar and shove it in' approach fwiw). In a nutshell - it all boils down to what feels good on 'your' wrist and what do you like. My advice, is pick up a used Iso from the forums and try it out, if you don;t like it, you can always turn around and put it up for sale here (good Iso's on the forums rock between $70-$90 depending on condition). Hope this helps, and good luck :)
 
#15 ·
Sorry - this thread could use a few more pictures. It's very hard to 'visibly' see how the Darth sits between the (2) straps; however, trust me the fit is different on my 7.25 wrist. The lume shot really doesn't help, just like the way it looks :) (btw - I also wish my SBBN017 glowed like the Darth).
 

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#16 · (Edited)
Thanks for the reply.
I am still using the OEM strap as my go-to rubber strap and have yet to purchase an iso...
I'm sure I eventually will because of FOMO regarding something with that many props and accolades.
Still happy with Seiko rubber as well as a variety of NATOs, two piece nylons NATO-like straps, and canvas.

/OT rant:
BTW I read your post regarding your new darth on the big Tuna thread with interest because I had the SBBN025 new Darth first, and then only recently have picked up an SBBN007. Opposite order as you (yours isnt 007 but you get my point... I had a new-hands watch first and then in turn bought an old-hands watch.)

I do agree 100%. I find the old hands beautiful. They look awesome. They're prettier and classier and they are just what one thinks of when they think of the Tuna. From a pragmatic standpoint my eyes pick up the new hands much quicker in almost any condition. If I glance at the watch under any kind of duress I can most definitely get the time in my head much easier and faster with the new hands. For whatever it's worth.

I do appreciate the beauty and heritage of the old hands and that's part of why I wanted the SBBN007, but having used both.... functionally the new hands are arguably more useful in many applications. I won't call either my favorite.

/end OT rant.


EDIT: thanks for the pics... I don't think I would mind a minor height-boost as I do wear it on NATOs with no complaints. Primarily just sticking with OEM from an 'aint broke dont fix' standpoint.
 
#17 ·
Late here also, but I could save you some money!

i have an Isofrane for my Spring Drive, and it's a great strap....softish and pliable, very comfy....but not cheap.

i just got a Borealis Cascais, and as part of my purchase I ordered several of their ISO style straps, as I had heard great things about them.....

oh boy

softer and more comfy than my ISO, pretty much identical in design, and did I mention the price?

$25

each

here is a blue 22mm on my PADI TUNA

Watch Analog watch Watch accessory Wrist Strap


Don't get me wrong, the stock straps on the Tunas are some of the best Seiko makes, but they are not a shade on the Borealis ISO!

and did I mention the price?

$25!

so for $100 I picked up 4, for half the price of what a new (real) ISO is going for!
 
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